How to Send an Invoice on WhatsApp — UK Tradesperson Guide
WhatsApp is already the conversation. Sending the invoice through the same channel removes the gap between job done and money in the bank — but only if it's a professional, HMRC-compliant invoice, not a text message. Here's how UK tradespeople invoice from WhatsApp properly.
If you booked the job on WhatsApp, agreed the price on WhatsApp, and confirmed the appointment on WhatsApp, sending the invoice on WhatsApp is the natural next step. The customer is already in the conversation. The notification will actually be seen. The Stripe payment link is one tap away. The only thing that has to change vs the kitchen-table accounting approach is the document itself: a text message saying 'that'll be £350' isn't an invoice — it's a verbal price in writing. Here's how to do it properly.
What an HMRC-compliant invoice must include
Whether you send the invoice on WhatsApp, email, or paper, the content has to meet HMRC's requirements. If you're a sole trader (not VAT-registered) the minimum is:
- Your name and business name
- Your business address and contact details
- Customer's name and address
- A unique invoice number (sequential — no gaps, no repeats)
- Invoice date and the date the work was supplied (if different)
- A clear description of the work / goods provided
- The total amount due
- Payment terms (e.g. 'Payment due within 30 days')
- How the customer should pay (bank details, payment link, etc.)
If you're VAT-registered, the requirements expand: VAT registration number, VAT rate per line item, net amount, VAT amount, and gross total. Mixed-rate jobs (some lines at 20%, others at 5% reduced rate for renovations of empty homes) need each rate shown clearly per line.
Trade qualifications belong on every invoice
For UK trades with regulatory registrations (Gas Safe, NICEIC, NAPIT, ELECSA, ECA, SELECT, Part P), your registration number belongs on every invoice and certificate. Customers — particularly landlords doing due diligence — look for these. Letting agents managing larger portfolios sometimes won't pay without seeing the registration number on the invoice. Display the number in the footer or near the supplier details.
The slow approach — PDF attached to a WhatsApp message
The most common 'invoice on WhatsApp' setup: tradesperson goes home after the job, creates the invoice in Word / Google Docs / a basic invoicing tool, exports as PDF, opens WhatsApp on their phone, navigates to the customer's chat, hits attach, picks the PDF, sends. This works — the customer gets a proper document — but the lag is the problem. If the job finishes at 4pm Friday and the laptop session happens Sunday evening, the invoice goes out 48 hours later. Cash-flow data is consistent: same-day invoices get paid faster than next-week invoices.
The faster approach — invoice from inside WhatsApp
The faster approach keeps the entire process inside WhatsApp. Message Wedge in plain English describing what you did, who for, and how much. AI parses the message, applies your VAT rate if you're registered, calculates CIS deduction if you mention it, prints your trade qualification, and generates a branded PDF in under 60 seconds. The PDF goes straight to the customer with a Stripe payment link — they tap, pay, money lands in your bank via Stripe Connect with Wedge taking 1% (capped at £50 per invoice).
A typical Wedge invoice message looks like: "Invoice Dave Smith £350 for emergency boiler call-out at 14 Acacia Avenue — £180 call-out, £100 labour, £70 for the diverter valve." The PDF lands in Dave's WhatsApp in 60 seconds with each line item broken out, your Gas Safe number in the footer, and a Stripe payment link he can tap from his phone.
Bank details on every invoice — keep the free option open
Even if you accept card payments via a payment link, print your bank details (sort code and account number) on every invoice as well. Some customers will always prefer bank transfer because it costs them nothing — and you save on the card processing fee. With Wedge, your sort code and account number print on every invoice automatically alongside the Stripe link, so the customer chooses.
Multi-property invoices for landlords and letting agents
If you do regular landlord work — EICRs, CP12s, void-period repaints — your customers will often want one invoice covering multiple properties, each as a separate line item. This is cleaner for the landlord's accounting than receiving six separate invoices for six properties. With Wedge, just mention each address in the WhatsApp message and the multi-property invoice generates automatically with one reference number and per-address line items.
Same-day invoicing changes cash flow
The cash-flow impact of moving from end-of-week invoicing to same-day invoicing is significant. Same-day invoices typically pay within 14 days; week-later invoices typically pay within 28-35. For a self-employed tradesperson with £80,000 annual turnover, that's a £6,000+ working capital improvement just from changing when the invoice is sent — not what's on it. The single highest-leverage habit change a UK tradesperson can make is invoicing before they leave the customer's drive.
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