What to Put on an Invoice: The Complete Checklist

A complete invoice needs your details, the client's details, a unique invoice number, the issue date and due date, clear line items with descriptions and prices, the subtotal, any tax, the total, and your payment details. Miss any of these and you give the client a reason to delay paying while they come back to ask. A complete invoice gets processed without a single follow-up question, which is the whole goal.

Think of an invoice as a document that has to be paid by someone who has never spoken to you. The client's finance team should be able to process it cold, with no need to email you for the missing piece. Everything below exists to make that possible.

Your details and the client's details

Start with who is billing whom. Your section goes at the top: your full name or business name, your address, your email, and your phone number. If you are VAT or tax registered, your registration number belongs here too. If you are not, you simply leave it out.

Then the client's details: the company name, the specific person or department you are billing, and their billing address. If the client gave you a purchase order number or an internal reference, include it, because large organisations often will not process an invoice that is missing their PO reference. Sending the invoice to the right person also matters more than it sounds, since the person who commissioned the work is frequently not the person who pays it.

The invoice number and dates

Every invoice needs a unique invoice number in a sequential series, such as INV-001 or 2026-001. The number lets both sides reference the invoice unambiguously and keeps your records in order. The full approach is in how to number your invoices, and the rule is simply: unique, sequential, never skipped or reused.

You also need two dates. The issue date is when you send the invoice, and it is the date your payment terms count from. The due date is when payment is required, and it should appear as a real calendar date, not just a term. "Due 1 July 2026 (Net 30)" leaves nothing to interpret. How to set and phrase terms is in how to write clear payment terms on an invoice.

The line items

The line items are the core of the invoice, where you set out exactly what you are charging for. Each thing gets its own row with a description, a quantity, a unit price, and a line total.

Be specific in the descriptions. "Copywriting, 3,000 words at 0.12 per word, 360" tells the reader precisely what they are paying for. "Writing work, 360" invites a query. The more clearly each line states what was delivered, the faster the invoice clears, because the person approving it can see the value without asking you to explain it.

If the work spans different categories, separate them into distinct lines rather than lumping everything into one. A clear breakdown reads as professional and is easier to approve.

The totals and any tax

Below the line items, show the money clearly. Start with the subtotal, the sum of all line totals before tax. Then add any tax, such as VAT or GST, as its own line showing the rate and the amount. Then the final total, which is what the client actually pays.

If you are tax registered, the tax must appear as a separate line so the client can reclaim it, and your registration number must be on the invoice. If you are not registered, there is no tax line. Where you work across currencies, state the currency explicitly so there is no ambiguity about whether 1,000 means euros, pounds, or dollars. The mechanics of adding tax are in how to add VAT to an invoice.

How to pay

An invoice that does not say how to pay it is an invoice that gets paid late. Put your payment details clearly at the bottom: the account name and number with sort code for domestic bank transfer, or the IBAN and BIC for international, or your payment-link address, or whatever methods you accept.

If the person reading the invoice cannot work out how to send you money without contacting you first, you have built in a delay. List every accepted method with the details needed for each, so the client can pay immediately by whichever route suits them.

A quick checklist

Before you send any invoice, run down the list. Your details and tax number if registered. The client's details and any PO reference. A unique invoice number. The issue date and a calendar due date. Clear, specific line items with quantities and prices. The subtotal, any tax line, and the total. Your payment details. Your terms, including the late-payment note if you use one.

If every item is present, the invoice is complete and ready to be paid without a follow-up. The full walk-through of building one from scratch is in how to create an invoice.

The simplest way to make sure nothing is missing is to use a tool that prompts for each field. The free invoice generator produces a clean, numbered invoice with all of these elements in place, running in your browser with no signup and nothing stored on a server. Fill it in once, and the structure carries to every invoice after.

Common questions

What are the essential things every invoice must have?

Your details and tax number if registered, the client's details and any purchase order reference, a unique invoice number, the issue date and a calendar due date, clear line items with descriptions, quantities, and prices, the subtotal, any tax line, the total, and your payment details. If every one of these is present, the invoice can be processed by someone who has never spoken to you, which is the whole goal. A missing field is a reason for the client to come back and ask, which delays payment.

Do I need a logo or a registered company to invoice?

No. An invoice needs the right information laid out clearly, not branding or a particular legal status. A sole trader can invoice under their own name, and a plain, well-structured document is every bit as valid as a designed one. Even so, a clean and consistent layout does signal that you take your business seriously, which can make clients more comfortable paying promptly. The content is what makes the invoice valid. The presentation is what makes it look professional.

How should I describe line items on an invoice?

Specifically enough that the person approving the invoice can see exactly what they received. "Copywriting, 3,000 words at 0.12 per word, 360" is clear. "Writing work, 360" invites a query. Give each distinct piece of work its own line rather than lumping everything together, and include a description, quantity, unit price, and line total for each. The clearer each line is, the faster the invoice clears, because the approver does not need to ask you to explain it.

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Related articles

• How to Create an Invoice: A Practical Guide
• How to Write Clear Payment Terms on an Invoice
• How to Number Your Invoices: A Simple System