How to invoice a client (freelancer's guide)

Keel Guides · Ilura Technology

To invoice a client, send a document with your name and contact, the client's name, a unique invoice number, the date and due date, a clear line-item description with amounts, the total, and how to pay. Keep it to one page, send it the day the work is accepted, and state a specific due date — 'due July 30', not 'net 30' — so there is no ambiguity about when you expect payment.

A freelance invoice has one job: get you paid, quickly, without a follow-up. Most late payments trace back to an invoice that made the client work too hard — unclear amount, no due date, no obvious way to pay. Fix those and you fix most of your cash flow.

What every invoice needs

Keep it to a single page with these fields:

You — your name (or business name) and contact.
The client — who is being billed. On larger jobs, add their address.
A unique invoice number — INV-2026-0007. It makes every invoice traceable and looks like you’ve done this before.
Dates — issued, and a specific due date.
Line items — what you did, quantity if relevant, and the amount. Plain descriptions the client recognises.
The total — big and unmissable.
How to pay — bank details, a link, or a QR code.

That’s it. Extra polish is fine; missing fields are what cause delays.

Say “due July 30,” not “net 30”

“Net 30” makes the client do arithmetic and gives them room to interpret. A calendar date does not. Name the day you expect payment, and most clients simply pay by it.

Send it fast, and make paying frictionless

Two habits move the money:

Invoice the day the work is accepted. Momentum is on your side while the deliverable is fresh.
Put payment one tap away. A payment link or a scannable QR code on the invoice removes the “I’ll do it later” gap where invoices go to die.

Do it in under a minute

Keel is built to make this the fast part of your week: pick a client, add a line, and send a clean PDF — or just describe the invoice in words and let Apple Intelligence draft it on your iPhone for you to confirm. You can drop your own payment link on as a QR code so the client pays without hunting for details, and it all happens on device, with no account. The invoice that used to take ten minutes takes one.

Quick answers

What has to be on a freelance invoice?: Your name and contact details, the client's name, a unique invoice number, the issue date and a clear due date, a description of what you did with the amount, the total owed, and a way to pay. If you charge sales tax or VAT you must show it separately; most freelancers billing services do not.
When should I send an invoice?: Send it the moment the work is delivered and accepted, not at the end of the month. The sooner a correct invoice is in the client's inbox, the sooner the clock starts — and the fresher the work is in their mind, the less it gets questioned.
How do I make it easy to get paid?: Put the payment method right on the invoice: a bank detail, a payment link, or a QR code the client can scan. Every extra step between reading the invoice and paying it is a chance for the payment to stall.

Run your money on your own phone

Keel — invoice, receipts, and one honest number.

The on-device financial brain for a company of one. Free to start, no account, nothing readable leaves your iPhone.

On-device · No account · Data Not Collected

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