What to put on an invoice

An invoice has one job: to get you paid, without a second email. Most of the ones that go unpaid for six weeks are not unpaid because the client is difficult. They are unpaid because something on them made it impossible for the person in accounts to process the thing on the day it landed.

Here is what belongs on one, in the order it matters, and why.

The eight that are not optional

1. The word “Invoice”

It sounds too obvious to state. It is not. A document headed “Statement” or “Summary” can be routed to the wrong pile, or treated as an estimate that does not need paying yet. In several countries a document has to say what it is before it counts as a tax invoice at all.

2. A unique invoice number

The single most-skipped field, and the one that causes the most trouble. Accounts departments key payments against a number. Without one, your invoice cannot be referenced in their system, and chasing it later means describing it — “the one from March-ish?” — instead of quoting it.

Any consistent sequence works: 001, 002, 003, or 2026-014, or a per-client prefix like NORTHWIND-007. Two rules only: never reuse one, and never skip backwards. Auditors read a gap in a sequence as a deleted invoice.

3. Your full business name and address

The legal name you trade under, not just your logo. If you are incorporated, the incorporated name. If a client’s finance system cannot match the name on the invoice to the name on the contract or the bank account, payment stops until someone asks a question.

4. Their full business name and address

Addressed to the company, not to your day-to-day contact. “Attn: Sarah” is useful; “To: Sarah” is not an invoice to a business. If they gave you a purchase order number, put it on — an invoice with a PO number usually skips a whole approval step.

5. The invoice date, and the due date

Both, as actual dates. “Net 30” requires the reader to do arithmetic and gives them room to do it generously. “Due 14 September 2026” does not. Writing the month as a word rather than a number also removes the 03/04/2026 ambiguity between North America and everywhere else.

6. A description of what you actually did

Specific enough that someone who was not in the room can approve it. “Consulting services” invites a question. “Brand photography, 14 Aug, half day, 40 edited images” does not. One line per distinct thing, with quantity and rate shown separately from the total, so the arithmetic is visible.

7. The amounts, broken out

Subtotal, then any discount, then tax as its own line with its own rate, then the total. Never one number. A client who cannot see how you reached the total will ask, and that question costs you a week.

8. How to pay, and the currency

The payment method spelled out — a payment link, an e-transfer address, or full bank details. And the currency named explicitly. $ alone is genuinely ambiguous between Canadian, US, Australian and several other dollars, and the difference has been a real dispute more than once. Write CAD, USD or AUD.

The four that get missed

Your tax registration number

If you are registered for GST, HST, VAT or the local equivalent, the number goes on the invoice. In most countries your client cannot reclaim the tax without it, which means they will come back and ask — and until they do, they may simply not pay.

What happens if it is late

One line is enough: “Accounts unpaid after 30 days may be subject to 2% monthly interest.” It is rarely enforced. It changes behaviour anyway, because it moves your invoice up the pile when someone is deciding which to pay this week.

A payment link

A button beats an account number every time. Retyping bank details is friction, and friction on an invoice is measured in days. If you take Stripe, PayPal, Square or Wise, put the link on the document itself.

A human sentence

“Thanks — it was a pleasure working on this.” It costs nothing, and an invoice is often the last thing a client reads from you before deciding whether to book you again.

What does not belong

• A watermark. If your invoicing tool brands your document, it is advertising to your client at your expense.
• Your whole price list. Invoice what was agreed. A menu invites renegotiation at exactly the wrong moment.
• Anything you have not agreed. An unexpected line on an invoice is how a good working relationship ends.

One thing to check before you send

Add the lines up yourself. Rounding bugs in invoicing software are more common than you would like — a document whose printed lines do not sum to its printed total is a document an accounts department is obliged to reject.

The Bindery invoice generator has a field for every item on this page, remembers your business details for next time, and produces the PDF in your own browser — no account, and no watermark.