What to Include on an Invoice: The Complete Checklist

The Invoice Checklist at a Glance

Use this as a pre-send check. Each row gives the field, what to write and an example. The first twelve belong on every invoice; the tax rows apply once you are registered to charge tax.

• -1. Document title | The word 'Invoice' (or 'Tax Invoice' where required) | INVOICE
• -2. Invoice number | Unique and sequential, never reused | INV-0042
• -3. Issue date | The date you issue the invoice | 10 October 2026
• -4. Your details | Legal or trading name, address, email, phone | Jane Smith Design, 14 Mill Lane, Leeds LS1 4AB
• -5. Client details | Client's legal name and billing address, plus a contact | Northwind Ltd, Accounts Payable, 2 Quay St, Bristol BS1 6AA
• -6. Description of each item | What was supplied, in plain words | Brand identity: logo, colour palette, type guide
• -7. Quantity and unit | Hours, days, units or 1 for a fixed fee | 1 project
• -8. Unit price | Price per unit, before tax | £2,400.00
• -9. Line total | Quantity × unit price | £2,400.00
• -10. Subtotal, discount, total | Sum of lines, any discount, the amount due | Total due £2,880.00
• -11. Due date and payment terms | The rule and the calendar date | Net 30, due 9 November 2026
• -12. Payment instructions | Bank details or your own payment link, and the reference | Sort code 12-34-56, Acc 12345678, ref INV-0042
• -13. Tax registration number (if registered) | Your VAT, GST or sales-tax ID | VAT No. GB123456789
• -14. Tax rate and tax amount (if registered) | Rate per line or per invoice, and the tax total | VAT 20%: £480.00

The Fields Every Invoice Needs, Explained

The title matters more than it looks: 'Invoice' tells the client's accounts team this is a demand for payment, not a quote, estimate or receipt. The invoice number lets both sides refer to one document without confusion; most tax authorities require numbers to be unique and in sequence, so pick a format like INV-0001 or 2026-001 and stick to it (the free tool at /invoice-number-generator can suggest one). The issue date starts the clock on payment terms and decides which tax period the sale falls in. Your details and the client's details identify the parties: use legal names, because 'Mike at Northwind' is not someone an accounts system can pay. Descriptions should let a stranger match the invoice to an approved job, and quantities and unit prices let the client check your maths. Finally, the totals block, the due date and the payment instructions are what actually get you paid. An invoice without a due date gets paid when it is convenient; one without payment details gets an email asking how to pay.

Extra Fields Required for VAT, GST and Sales Tax

Once you are registered for a consumption tax, the invoice becomes a tax document and the rules tighten. The details differ by country, so treat this as a general guide and confirm with your tax authority or accountant. In the UK, a full VAT invoice must show your VAT registration number, the time of supply (tax point) if it differs from the issue date, the VAT rate and the amount of VAT, and the total excluding VAT, alongside the usual fields. EU member states follow a similar list set by the VAT Directive, and for cross-border business-to-business sales the customer's VAT number and a note such as 'Reverse charge' are usually needed. In Australia, a GST-registered business must label the document 'Tax invoice' and include its ABN; for sales of A$1,000 or more, the buyer's identity or ABN is also required. In the United States there is no federal invoice format, but if you collect state sales tax, show it as a separate line. If you are not registered, do not show a tax line at all.

Fields That Are Optional but Worth Adding

These are rarely required by law, but each one removes a reason for the client to delay payment.

• -Purchase order (PO) number: many larger companies will not process an invoice without it.
• -Service period or delivery date: 'Work performed 1–30 September 2026' answers the first question an approver asks.
• -Late payment terms: a fee or interest rate, stated in advance. See /blog/invoice-payment-terms for wording.
• -Your logo and an accent colour: they make the invoice recognisable in a crowded inbox.
• -A short thank-you note: it costs nothing and sets a friendly tone.
• -Signature: useful for clients, public bodies or customs authorities that ask for it.

What Not to Put on an Invoice

A tidy invoice gets processed faster. Leave out anything that makes it harder to read or to file. Do not include a tax line if you are not registered to collect tax. Do not bundle unrelated jobs into one vague line such as 'Work in September'. Do not change the number format halfway through the year. Do not include a 'pay now' button you have not tested; if you add your own payment link, paste the full link in the notes and check it works. And do not send a receipt when you mean an invoice: an invoice asks for money, a receipt confirms it has been paid (the full difference is at /blog/invoice-vs-receipt).

A Filled-In Example

Here is how the checklist looks on a real invoice for a UK designer registered for VAT. Header: INVOICE, number INV-0042, issued 10 October 2026, due 9 November 2026 (Net 30). From: Jane Smith Design, 14 Mill Lane, Leeds LS1 4AB, [email protected], VAT No. GB123456789. Bill to: Northwind Ltd, Accounts Payable, 2 Quay Street, Bristol BS1 6AA, PO 7781. Notes: 'Thank you for your business. Please pay by bank transfer to Jane Smith Design, sort code 12-34-56, account 12345678, quoting INV-0042.'

• -Brand identity: logo, colour palette and type guide | 1 | £2,400.00 | £2,400.00
• -Business card design, two-sided | 1 | £300.00 | £300.00
• -Discount (returning client, 10%) | | | minus £270.00
• -Subtotal after discount: £2,430.00
• -VAT at 20%: £486.00
• -Total due: £2,916.00

How to Tick Every Box Without Starting From Scratch

The easiest way to make sure nothing is missing is to use a layout that already has every field. Invoita's free generator at /generator starts with all of the fields above in place: your details, the client, number, dates, line items, discount, one tax rate per invoice with individual lines markable as not taxable, notes for payment instructions, and an optional signature. Anything you do not need can be removed, and the title and main labels can be renamed, so 'Invoice' can become 'Tax Invoice' where your rules require it. It supports 25 currencies and four page sizes, exports a PDF without a watermark, and needs no signup. You can preview the six designs at /invoice-templates. If this is your first invoice, our step-by-step guide at /blog/how-to-make-an-invoice walks through filling each field in order.

Before You Hit Send: A 30-Second Check

Run through these five questions on every invoice. They catch the mistakes that cause most payment delays.

• -Is the client's legal name and billing address correct, with a PO number if they use them?
• -Is the invoice number new and in sequence?
• -Does the total match the agreed quote, and is tax shown only if you are registered?
• -Is there a calendar due date, not just 'Net 30'?
• -Could the client pay right now using only what is on the page?

Frequently Asked Questions

Short answers to the most common questions about invoice requirements.

• -What are the legal requirements for an invoice? It depends on the country and on whether you are registered for VAT, GST or sales tax. Almost everywhere expects a unique number, an issue date, both parties' names and addresses, a description of what was supplied, and the amount due. VAT and GST invoices add your tax number, the tax rate and the tax amount. Check your local tax authority's guidance for the exact list.
• -Does an invoice need to be signed? Usually not. Very few jurisdictions require a signature on a commercial invoice. Some clients, public bodies and customs authorities prefer one, so it is worth being able to add it. Invoita lets you draw or upload a signature and remove it when it is not needed.
• -Do I need an invoice number if I only have one client? Yes. A unique, sequential number is how you, your client and a tax inspector tell invoices apart, and many tax authorities require it. INV-0001, INV-0002 is enough.
• -Should I include my bank details on the invoice? Yes, unless you only accept payment another way. Clients pay faster when the payment instructions are on the invoice itself. Include the account name, the account number or IBAN, the bank's SWIFT/BIC for international payments, and the reference to quote.
• -What is the difference between a due date and payment terms? Payment terms are the rule (for example Net 30, meaning 30 days after the invoice date). The due date is the result of applying that rule, written as a calendar date. Put both on the invoice so nobody has to count days.

Wrapping Up

An invoice needs to answer four questions without the client having to ask: who is billing whom, for what, how much, and when and how to pay. Twelve fields cover that on every invoice; registering for VAT, GST or sales tax adds your tax number, the rate and the tax amount. Keep the checklist above next to your invoicing tool, or use a generator that already has every field laid out, and your invoices will go straight through the client's approval process instead of coming back with questions.