How to run a client consultation as a solo beauty pro

June 25, 2026 · 21 min read · back to blog

A consultation that stays only in your memory is a conversation. A consultation that is written down — sent back to the client before the appointment begins, or documented in a note before you pick up a tool — is documentation. The difference is not formality. It is whether, when a client files a dispute for "service not as described," you have a contemporaneous record of what you agreed the service would describe. Without documentation, the only description of what the client expected is the client's description. With it, you have your notes from before the appointment started. Most outcome disputes come down to that gap.

The consultation gap

The typical solo beauty pro consultation works like this: the client arrives, they talk in the chair for a few minutes about what she wants, you review the reference photos on her phone, you agree (verbally) on what is happening today, and you begin. The consultation happened. But it left no record.

That is not a small problem for outcome disputes. A Stripe chargeback for "service not as described" is evaluated on documentation. The issuing bank asks: what did the merchant represent the service would be, and what did the client receive? If your answer to the first question is "we talked about it before I started," you are arguing memory against memory — and the client filed first, which means her version of the conversation is already in the dispute record.

The consultation gap is not about whether you did a consultation. Most solo beauty pros consult every client, every appointment. It is about whether the consultation produced a retrievable record before the appointment started. That is the distinction that changes your dispute position.

This guide is about the consultation as a documentation step — not just a rapport-building conversation. It is distinct from the pre-booking intake form (which covers what to ask before the appointment) and from the color-specific consultation scoping guide (which goes deep on reference image protocol and chemical history for colorists). This guide covers the consultation structure that applies across all beauty service verticals — what to cover, in what order, and how to document it in a form that is retrievable when you need it.

When the consultation happens changes what it can do

Consultations can happen at three points in the appointment cycle, and the timing determines how much protection the consultation actually provides.

Pre-appointment (DM or video, before the client arrives): This is the highest-value timing. Scope is settled before both parties commit. Reference photos can be requested and reviewed with enough lead time to address misalignments before the appointment date, not in the chair when the client is sitting in front of you and both parties feel pressure to proceed. Contraindications can surface with time to reschedule rather than turn a client away at the door. The summary sent in the DM thread before the appointment becomes a written record that the client read — she confirmed the appointment after seeing it.

In-chair at appointment start, before beginning: Still valuable, still worth documenting. The difference from pre-appointment is that you are now operating with a client who is already physically present and has already committed to being there. That creates soft pressure on both sides to proceed even when scope is not fully resolved. Notes taken in-chair before starting are still a contemporaneous record — still useful in a dispute — but they are harder to send back to the client for written acknowledgment before beginning. The pre-start confirmation statement (covered below) fills some of that gap.

No consultation or consultation only in memory: Both parties proceed with their own internal model of what the appointment will produce. These models diverge at a predictable rate — most often on outcome (especially for color and PMU), scope (especially for add-ons and multi-session services), and duration (especially for complex services scheduled for the first time). No documentation means no record. A dispute about a service with no consultation notes is resolved purely on Stripe's evaluation of your booking records and whatever the client provides.

The fix is not to run a longer consultation — it is to run the same consultation you already run, but produce a written record before starting. For most services, that takes three to five minutes. For complex services — color corrections, PMU procedures, extension installations — it takes ten to fifteen. The return on that time is a documented scope agreement that holds in a dispute.

The five elements of a documented consultation

A complete consultation note has five elements. You do not need all five for every appointment — a returning client with a consistent service may only need elements two and five. But every first-time client and every complex or multi-session service should have all five, documented and sent or saved before the appointment begins.

1. Desired outcome in the client's own words

Not your interpretation — her description. Write down what she said she wants, in approximately the words she used. If she said "I want to go lighter" write "lighter." If she said "I want that icy platinum blonde," write that exactly. The specificity is what makes the note useful later.

For short-form DM consultations, ask one open question: "Can you describe what you're hoping to leave with?" and use the client's response verbatim in your note. She has already written her desired outcome in her own words; you only need to document it.

For in-chair consultations, paraphrase what she said and say it back to her: "So what you're describing is moving toward [X] — is that right?" Her "yes" is the verbal confirmation; your note of what she confirmed is the written record.

2. Reference materials reviewed

List every reference photo or material reviewed, with a one-sentence description of what it represents as direction. Not what the photo shows — what it means as direction for this client's service.

This distinction is the most important element of the reference photo protocol. A reference photo is direction, not a specification. The photo was taken in different lighting, on a different person, with different starting hair/skin/nail conditions, by a different professional using products and techniques you may not have. Saying "she showed me this photo" does not capture what she wants. Writing "reference photo: level 9 ash blonde result — client wants this tone and cool undertone, not the length or texture (she has straight hair, the reference has waves)" captures what she is asking for as direction and what she is not expecting as a literal match.

Two questions to ask for every reference photo:

1. "What specifically about this photo do you want to match?" — this surfaces the actual directive (the tone? the placement? the dimension?)
2. "Is there anything about this photo that doesn't reflect what you want?" — this surfaces the mismatches the client already sees (she may know the texture is different, the length is different, the backdrop is different; getting her to say it changes what she expects)

Document both answers in your note. If she says "just the color, not the length or waves," write that. That sentence is the scope of the reference photo.

3. Starting point assessment

What is the current state that the service is starting from? This element is vertical-specific — the relevant factors differ by service category. But the principle is the same across all verticals: document where you are starting from before you start, so that any outcome question can be evaluated against the documented baseline.

Starting point is what makes "before photos" and consultation notes work together. The before photo captures the visual baseline; the starting point note captures the clinical or technical baseline — the information that does not appear in a photo but that determines what is achievable in the session.

For colorists: current level and tone, visible porosity signs, any known chemical history, last service date and product used.

For lash artists: natural lash density, current length and curl, condition of previous extensions or residue, any sensitivity history.

For nail technicians: nail health (any lifting, damage, thin spots), current product on the nail, length and shape preference history.

For brow artists and PMU: skin type (oily, dry, combination), previous PMU work or pigment history, any contraindications identified in the intake form.

For mobile groomers: coat condition (mats, tangles, undercoat), skin condition (any irritation, lesions, previous reactions), behavioral notes from prior visits or owner disclosure.

4. Session limitations

What can and cannot be achieved in the current session, based on the starting point? This is the honest framing that prevents the majority of "you didn't finish" disputes.

Most outcome disputes on complex services are not about the quality of the work — they are about the distance between what the client expected to leave with and what one session can realistically produce. Documenting the limitation before starting converts a potential dispute into a disclosed and acknowledged constraint.

The framing is not apologetic: "You have significant warmth at your roots, which means today's session will lift and tone to approximately a level 7 ash — we'll need two more sessions to reach the level 9 result in your reference photo. Does that timeline work for you?" Write down her answer. If she says "yes, I understand," document it. If she says "I thought we could do it today," that is a conversation to have now, not after the appointment.

For services where the limitation is inherent to the modality — PMU healing, lash growth cycles, nail repair — the limitation is clinical rather than a function of starting point. State it in the same format: "Microblading heals over four to six weeks. What you see leaving today will look significantly different after healing — strokes will appear lighter and there may be some flaking in the first week, which is normal. Your touch-up appointment at eight weeks is when we fine-tune the shape and density." Document that you disclosed this and that the client acknowledged it before beginning.

5. Agreed scope and price

What specifically will be performed in this session, and at what price? This is the scope agreement — the element that your booking policy points to as the definition of what was booked.

For returning clients with consistent services, this is usually unchanged from the booking confirmation. For new clients, complex services, or anything that diverged from the original booking scope during the consultation, write it explicitly: "Today: full set classic lashes, $120. No fill included — next fill appointment should be booked within three weeks."

If scope changed during the consultation — for instance, the client arrived for a highlight and after reviewing the starting point you both agreed to add a toner — note the change and the price adjustment before beginning. This is the add-on authorization that your add-on pricing policy requires: a scope change agreed and documented before the work begins, not discovered at checkout.

How to document the consultation

The format of the documentation matters less than whether it is retrievable. Three formats work; one is significantly more defensible than the others.

DM summary sent to client before the appointment: This is the most defensible format for dispute purposes. You send a text or DM to the client with the five-element summary — what she said she wanted, what references you reviewed and what they represent, where she is starting from, what can and cannot be achieved today, and what is happening and at what price. She reads it. She shows up. Her showing up after receiving the summary is implicit acknowledgment that she reviewed the terms. For a Stripe dispute: you have a timestamped message in a thread showing you sent the scope summary before the appointment, and a subsequent appointment that proceeded. That is contemporaneous documentation.

For pre-appointment consultations done by DM, this is easy — the consultation is already in the DM thread. Screenshot and save it; the thread itself is the record.

For in-chair consultations, the DM summary is sent at the end of the consultation and before beginning the service: "Just confirming what we talked about — [3-sentence summary]. Ready when you are!" Two minutes. Send before picking up a tool. Screenshot the send.

In-system consultation notes: If your booking system supports client notes (Square Appointments, Vagaro, and most booking tools do), a pre-service note saved to the client record is a contemporaneous document with a timestamp from your system. Less defensible than a DM send because the client has not seen it, but still a contemporaneous record that you can produce in a dispute showing what you documented before starting.

Notes app or paper: The least defensible format because there is no timestamp, no evidence that the client saw the terms, and no authentication that the note was made before the service rather than after. Still better than no documentation, especially if you photograph the note immediately after writing it (photos are timestamped). But upgrade to one of the two formats above for any service where outcome disputes are likely — color corrections, PMU, multi-session extensions.

For most returning clients on routine services, in-system notes are sufficient. For new clients and complex services, the DM summary is worth the two minutes it takes.

The pre-start confirmation statement

Before picking up any tool — before applying any product, before turning on any equipment, before beginning any service — state the scope of the appointment out loud and wait for a verbal response.

One sentence: "Today we are doing [X]. By the end of this appointment you will have [Y] — that's [any relevant limitation or next step]. Ready to go?"

This is not a repetition of the consultation — it is the final scope lock before commitment. The client has heard the service described at booking, in the consultation, and now at the moment before starting. Any misalignment that survives to this point surfaces now, with nothing spent and nothing irreversible yet done.

For color services: "Today we're lifting and toning to around a level seven ash — you'll be noticeably lighter and cooler than you came in. We'll need two more sessions for the level nine we talked about. Sound good?" Wait for "yes." That verbal yes, immediately before starting, is the moment of informed consent on scope.

For lash services: "Today is a full set in the D-curl, classic — you'll leave with full coverage and volume. I'll send you the aftercare guide when you're done. First fill at three weeks to keep them looking full. Ready?" The service described. The next step named. The aftercare commitment made. All before starting.

For PMU: "Today is the initial microblading procedure. What you'll see leaving today is your strokes before healing — they'll look darker and crisper than the healed result. The healing process takes four to six weeks; the strokes lighten and soften as you heal. We'll see the true healed result at your touch-up at eight weeks. Any questions before we get started?" The healing timeline disclosed again, verbally, at the moment before commitment. For a procedure with a four-to-six-week feedback delay, this statement is the last chance to surface misaligned expectations before any irreversible work begins.

The pre-start confirmation is verbal and does not add to your written documentation — but it is the second line of defense, after the consultation note, and the first point at which the client can stop the appointment before it begins. Many disputes are prevented here, because clients who had unresolved questions about what they were getting speak up when directly asked "ready to go?" rather than saying nothing and discovering the answer at the end.

The consultation note as a dispute document

Stripe chargebacks for "service not as described" are evaluated on what the merchant represented the service would be. Your documentation package for a dispute should include three things: your booking policy (what the general terms were), your booking confirmation (what service was booked and at what price), and your consultation note (what outcome was agreed to, what limitations were disclosed, and what scope was confirmed before starting). The consultation note is the third document, and it is the one that directly addresses "not as described" — because it describes, in writing, what you and the client agreed the service would produce.

Without a consultation note, the only description of the service is the one the client provides in her dispute narrative. She will describe what she expected to receive — the reference photo result, the interpretation she put on your words, the outcome she assumed was included in the price. You will describe what you performed — the service you booked, the constraints you explained, the scope you agreed on. With no documentation, the dispute becomes your word against hers, and the bank resolves ambiguous disputes in the cardholder's favor.

With a consultation note — especially a DM summary sent before the appointment with the five elements documented — your dispute response is: "Here is what the client told me she wanted [quoted from her message]. Here is what I told her we would do today and what limitations apply [your DM summary, timestamped before the appointment]. Here is the outcome I delivered [after photos]. The service was performed as described in the consultation record." That is a materially different dispute response than no documentation.

You are not guaranteed to win every dispute with documentation. But you are guaranteed to lose most disputes about outcomes where there is no record of what was agreed before the service began.

Vertical-specific consultation requirements

Colorists

Color work has the highest outcome-dispute rate among beauty service verticals, for two reasons: the result is permanent until it grows out or is corrected, and the gap between a reference photo and a realistic single-session result is often significant and non-obvious to the client.

Chemical history depth required for color consultations: last chemical service (color, bleach, relaxer, perm), developer volume used if known, number of chemical processes in the last twelve months, any at-home application in the last six months (box color is the most common undisclosed complication). The intake form should capture most of this; the consultation verifies and fills gaps. Document what you confirmed, not just what was submitted.

Before photos are non-negotiable: three angles minimum (front, crown, ends), taken before any product application. The before photo establishes the starting baseline for any dispute about what was present before your work began — pre-existing damage, banding, underlying warmth that affects the result.

Session limitation framing for corrections is the single most important consultation element for colorists: "Color correction work requires multiple sessions — lifting and removing previous color builds in stages to protect hair integrity. Today we are doing [specific step]. At the end of this session your hair will have [realistic description]. We'll need [X additional sessions] to reach the reference result." Say it. Document it. Get a verbal yes before starting.

The reference photo protocol for colorists: the two-question approach described above, applied specifically to tone (what undertone is she after?), level (where on the 1–10 scale?), and placement (all-over? balayage? highlights?). A client who shows you a platinum photo but is starting from a level 4 with chemical processing history has misaligned expectations about what is achievable in one session. The consultation is where you resolve this — not at the mirror after the toner is rinsed.

Lash artists

Retention disputes are the most common outcome dispute category for lash artists. A client whose extensions fall out faster than expected will interpret this as a service quality issue. Whether it is — or whether it is natural lash growth cycle, aftercare, or the starting condition of her natural lashes — is what your consultation note establishes.

Natural lash assessment before applying any extensions: density (sparse, medium, full), current length and curl, whether there is previous extension residue, and any visible damage or shedding. Photograph this assessment before starting. If a client whose lashes were in poor condition at assessment files a retention dispute, your pre-service photos and notes document what you were working with.

Retention risk disclosure: state verbally and note in writing that retention depends on natural lash growth cycle (extensions shed with the natural lash), aftercare adherence (oil-based products, rubbing, exposure to steam and chlorine reduce bond integrity), and that two to three weeks is the expected fill interval under normal conditions. A client who receives this disclosure before her first set has different expectations about lash longevity than one who receives it for the first time when she calls to complain.

Fill vs full-set scope: agreed and documented before starting. "Today is a full set — you're starting from scratch, and the fill interval begins now. Next fill at two to three weeks. After that fill, we'll assess whether you need another full set or can maintain on fills." This prevents the "I thought a full set lasted longer" dispute that appears when a client expects full-set retention and receives fill-appropriate retention.

Nail technicians

Nail health assessment before beginning: check for lifting on any previous product, thin or damaged areas, any signs of infection or contraindication. Photograph hands before starting. For any concerning finding, document that you disclosed it to the client before proceeding: "Noted significant lifting on ring finger — client is aware, proceeding with gentle removal and repair before new product application."

Art scope interpretation is the most important consultation element for nail technicians who do nail art. Before starting any art design: "Nail art is an interpretation of the reference — I'll match the color palette and design direction, but each nail is hand-done so the result will have some variation from the photo. Sound good?" One sentence. Get a yes. Note it. The majority of nail art disputes are about the gap between a reference photo (often studio-lit, on different nail shapes, by a different artist) and the client's in-person result. That gap is not a quality issue — it is a medium issue. Document the interpretation scope before starting.

Product application scope for high-risk products (acrylic, hard gel, builder gel): disclose before applying that these products require proper removal — not peeling or cutting — and that damage from improper self-removal is not a service quality issue. Note that the client received this disclosure. If a client peels off hard gel and returns with damage claiming your product damaged her nails, your note that you disclosed removal requirements before application changes the dispute picture.

Brow artists and PMU

PMU procedures have the longest feedback delay of any beauty service — the final healed result is not visible until four to six weeks after the procedure. This means the consultation is doing work across a timeline of weeks, not hours. Every disclosure you make before starting is a disclosure the client may not fully recall six weeks later when she evaluates her healed result. This is why PMU consultation notes are non-negotiable documentation, not optional.

Pre-appointment health questionnaire verification: confirm at the consultation that the questionnaire was completed and that no contraindications are present. Note the verification. If a client discloses a contraindication at the chair that was not on the questionnaire, that is a reschedule or decline decision — not a proceed-and-document decision.

Skin type impact on result: oily skin heals differently than dry skin. Microblading strokes may blur or disappear faster in oily skin; ombre powder brows often heal better and last longer for oily skin types. State this clearly and document it: "Client has oily skin — discussed that microblading strokes may have faster fading than on dry skin; considered ombre powder as an alternative; client prefers microblading, aware of potential faster fading." This prevents the "my brows faded in four months" dispute becoming a service quality claim when it is a skin-type outcome.

Healing timeline disclosure at the pre-start confirmation statement is mandatory: what the client sees leaving today is not the healed result, the healing takes four to six weeks, the strokes will appear lighter after healing, some flaking is normal. Document that you made this disclosure before beginning.

Touch-up appointment as clinical requirement: this should be in the booking policy and the initial consultation — the touch-up is when the shape and density are finalized after healing, not an optional upsell. If a client disputes her initial result without having attended the touch-up, your documentation that you disclosed the touch-up as part of the procedure and that the healed result is assessed at the touch-up is the relevant record.

Mobile groomers

Pre-groom welfare assessment is the consultation for mobile groomers — and unlike in-salon consultations that happen verbally in a controlled environment, the pre-groom assessment is happening at the client's location, often in the first few minutes after arriving, before the pet owner has left. This makes documentation especially important.

The pre-groom welfare assessment should be documented before beginning any grooming: coat condition (any mats, tangles, undercoat extent), skin condition (any visible irritation, lesions, hot spots, redness), behavioral notes (any anxiety, aggression, sensitivity documented by the owner or observed), and any health conditions that may affect the grooming session. Photograph coat condition before starting.

Coat condition add-on communication: if the coat condition requires additional work beyond the booked grooming service — dematting, undercoat removal, extended time for behavior management — communicate this to the owner before beginning, get authorization in writing (a text confirming "go ahead" is sufficient), and document the authorization before proceeding. A coat condition add-on disclosed after the groom is a charge the client disputes. One discovered before and authorized in writing is a service the client approved.

For any first visit with a new pet client: a brief assessment message to the owner after your pre-groom assessment and before beginning is the mobile groomer equivalent of the DM summary: "Before I start: [Dog] has some matting on her hindquarters and a small area of redness on her left flank. I'll work around the mat and gently remove what I can without cutting into the skin — the mat removal may require some trimming in that area. Anything else I should know before I begin?" Wait for a response. Document the send and the response. That exchange is the pre-service consultation record for mobile grooming.

Common consultation mistakes

1. Treating the consultation as a conversation rather than a documentation step

The consultation happened. You are certain you told her the color would need two sessions. She is equally certain you said it would be done today. Both of you are telling the truth about your memory of a conversation. The fix is not a better memory — it is a written record.

2. Using reference photos without writing what they represent as direction

"She showed me a photo" is not documentation. "She showed me a level 9 ash blonde result; she wants the tone and cool undertone — not the length or wave pattern; she confirmed the reference is about color direction, not a pixel match" is documentation. The difference is specificity about what the reference means as direction for this client.

3. Skipping session limitation framing on complex or multi-session services

If you know before starting that today's session cannot produce the reference result — because of chemical history, starting level, skin type, or the nature of the modality — that knowledge belongs in the consultation note, before you start. A limitation disclosed after the appointment is an excuse. A limitation disclosed and acknowledged before starting is an agreed constraint.

4. Sending the consultation summary after the appointment

A DM sent after the appointment confirming what was done is not a consultation record — it is an after-service summary. The dispute value of documentation comes from the timestamp: before starting, not after finishing. If the client disputes the outcome and you send her a message after the appointment describing the service, you have created a post-hoc record, not a pre-service agreement. Send the summary before picking up a tool.

5. Relying on verbal disclosures with no written follow-through

Verbal disclosures are not retrievable. If a dispute involves what you said verbally before starting — the session limitation, the reference photo scope, the healing timeline — your only evidence is your word that you said it. The client's only evidence is her word that you didn't, or that she didn't understand. Written documentation, sent in the DM thread or saved in your booking system, has a timestamp. Verbal disclosures do not.

6. Not updating the consultation note when scope changes mid-service

If scope changes during the appointment — a client asks to add a service, a starting point assessment reveals a complication that changes the plan — update your note before beginning the new scope. A consultation note that documents the original scope but not the mid-service scope change is a partial record. The change is where disputes most often arise: "I didn't agree to that extra charge" or "I didn't know that was going to change what we were doing." An in-session note update and a brief verbal confirmation of the change ("I want to add a toner since we're going cool — that's an extra $25, okay?") before proceeding fills the gap.

Three-year compound: two lash artists, same client volume

Both lash artists run a full-service lash studio, doing full sets and fills. Same pricing. Same client volume. Same service quality. The only difference is consultation documentation.

Lash Artist A runs in-chair consultations verbally, reviews references on the client's phone, and begins work. No notes. No DM summary. Retention disclosures happen verbally. Fill scope is discussed at the chair. In year one, she has three clients who file disputes: one for retention ("they fell out in a week"), one for outcome ("they don't look like the photo"), one for scope ("I thought a fill included more than this"). She wins the scope dispute after extensive back-and-forth (the booking confirmation supports her). She loses the retention dispute — no before photos, no retention disclosure record, bank rules for the client. She pre-emptively refunds the outcome dispute client to avoid a chargeback. Direct costs year one: $180 refund plus $20 chargeback fee plus approximately twelve hours of dispute management across the three cases. Year two: two more disputes, similar pattern. Year three: one dispute, one refund. Three-year total: approximately $480 in direct costs and twenty-five hours of dispute management time.

Lash Artist B runs the same consultations — same conversation, same reference photo review, same verbal disclosures — but at the end of the in-chair consultation and before starting, she sends a three-sentence DM to the client: the desired outcome in her words, what the reference represents as direction, what will be done today and the fill timeline. She photographs natural lash condition before applying extensions. She sends the aftercare guide within two hours of every appointment. Same client volume as Artist A. In three years: two clients contact her with concerns about retention. She responds within four hours with photos of the pre-service lash assessment, the aftercare guide send record, and a brief explanation of natural lash cycle. Both clients accept the explanation and rebook. No chargebacks. No refunds. Direct costs year one, two, and three: zero dollars in disputes. Time cost: approximately three minutes per new client for the DM summary, plus two minutes per appointment for the aftercare guide send.

The gap over three years: $480 and twenty-five hours, from two lash artists with the same client volume doing the same consultations — one of which produces a written record before starting.

Operational checklists

New client consultation protocol (15–20 minutes total)

• Ask one open outcome question: "What are you hoping to leave with today?" Write down her answer in her words.
• Review reference photos: ask the two-question protocol (what to match, what not to match) and document the direction as a description, not a photo label.
• Complete starting point assessment for your vertical: photograph before starting, note the clinical baseline relevant to your service.
• State session limitations: what can and cannot be achieved today, with any multi-session timeline framing if applicable. Get verbal confirmation.
• Confirm scope and price: name the service, what it includes, what is not included at today's price.
• Send the five-element DM summary to the client before starting: desired outcome, reference direction, starting point note (brief), session limitation if applicable, agreed scope and price. Keep it to three to five sentences.
• Screenshot the sent message.
• Give the pre-start confirmation statement verbally before picking up any tool. Wait for a verbal yes.
• Save or screenshot the before photo to the client record.

Returning client consultation protocol (5 minutes)

• Confirm the service and scope (same as last time, or any changes).
• Note any change in starting point since last visit.
• State the pre-start confirmation before beginning.
• Update in-system notes with any relevant changes from the prior visit.

Complex or multi-session service additions

• Add explicit session limitation framing to the DM summary: what today achieves, what requires future sessions, what the timeline is.
• For PMU: document skin type, contraindication clearance, and healing timeline disclosure. Keep a copy with the client record.
• For color corrections: photograph before from three angles. Document chemical history including any at-home applications in the last six months. Note which level and tone is realistic by the end of today's session.
• For new extension clients: photograph natural lash condition and density before applying any product. Note the retention disclosure was made verbally and sent in writing.

Mid-service scope change protocol

• Stop before beginning any new scope element added during the service.
• State the change and the additional charge verbally. Wait for a verbal yes.
• Send a one-sentence DM confirming the addition and the price: "Going ahead with the toner at +$25 as we discussed — just confirming that's good." Wait for a response before proceeding if possible; if the client is in the chair and responding is impractical, your sent message is the documentation.
• Note the scope change in your booking system.

If you want a booking system where the consultation note is linked to the appointment record — attached to the deposit confirmation and retrievable in a dispute export in under a minute — ChairHold is in early access at $9/month: one booking link, deposit to your Stripe, and the client record that makes every consultation document defensible from the first message.