What to include on an invoice: 12 fields

The checklist that stops a correct invoice being bounced back by accounts payable.

Most late payments are not disputes about money — they are invoices that could not be processed. A missing purchase-order number, the wrong legal entity, or an invoice with no due date all give the client's finance team a legitimate reason to park your invoice at the bottom of the pile. These are the twelve fields that prevent it.

The 12 fields

1. The word “Invoice” at the top. Not “bill”, not a logo alone — an obvious title so the document is classified correctly on arrival.
2. A unique invoice number. One continuous sequence, never repeated, never skipped. See how to format invoice numbers.
3. Issue date. The day the invoice was raised. This is also the date payment terms usually count from.
4. Due date. Stated explicitly, as a real calendar date. “Net 30” alone makes the client do arithmetic; a date cannot be misread. Check it with the due date calculator.
5. Your business name and trading address, plus an email or phone number for billing queries.
6. Your tax registration number (VAT, GST, ABN, EIN — whichever applies) if you are registered. Many jurisdictions require it for the client to reclaim tax.
7. The client's legal entity and billing address. The company that signed the contract, not the brand or the local office.
8. The purchase-order or reference number. If the client uses purchase orders, an invoice without the PO number usually cannot be paid at all. Get it before you start work.
9. Line items: description, quantity, unit rate, line total. Break the work into recognisable pieces. “Consulting — $8,000” invites questions; three named deliverables do not.
10. Subtotal, tax and total. Show tax as its own line with the rate, and never fold it into a single grand total. State the currency.
11. Payment instructions. Bank details or a payment link, plus the reference the client should quote so the payment can be matched.
12. Payment terms and any late-fee clause — for example “Net 14 — overdue amounts accrue interest at 8% p.a.”. Use the late fee calculator to size the rate.

What to add depending on the work

• Work period or project name — “Consulting services, 1–31 March 2026” or “Website redesign — phase 2”.
• Deposit and balance lines if you invoice in instalments. Label them: “Deposit (50%)”, “Balance on delivery”.
• Pre-approved expenses as separate lines, with receipts attached when the contract requires it.
• Discounts as their own negative line, so the client can see what the concession was worth.
• A short thank-you note in the footer. Not required, but it costs nothing.

What to leave off

• Your whole life story. Invoices are filed, not read. Keep descriptions to a line.
• Unapproved extras. A charge the client did not agree to turns the invoice into a negotiation.
• Rounded “estimates”. If the total is an approximation, say so or re-issue it — a wrong total is a reason to query the whole document.
• Confidential client data. Don't paste details into a description field that does not need them.

The 60-second check before you hit send

Ask five questions, in this order:

1. Is the invoice number new and in sequence?
2. Is there an explicit due date on the document?
3. Have I billed the entity that actually pays, and quoted its PO number?
4. Can a stranger pay this invoice without emailing me — are the payment details and currency correct?
5. Would I approve this invoice at a glance if I were the client?

Five yeses and the invoice will be paid on the normal cycle. Anything else and you will meet it again as an email in three weeks.

Keep the format fixed

Once your invoice format is right, stop redesigning it. The same layout, the same numbering scheme and the same terms every month is what lets a client's finance system process you quickly — and it lets you produce the next invoice in under two minutes. If you are unsure how payment terms should read, see net 30 payment terms explained; if you need to chase one that is late, use the payment reminder templates.

General invoicing practice, not legal or tax advice — required fields vary by country and by how your business is registered. The free generator prints a small “Made with InvoiceForge” credit; a $19 one-time Pro licence removes it and adds saved invoices.