The small business invoice: every field it needs, with a template

An invoice looks like paperwork, but it is really a request for money, and the easier it is to understand and act on, the sooner it is paid. Invoices that go unpaid are often invoices that raised a question: who is this from, what is this line, how do I pay?

This guide goes through every field a service business invoice needs, then gives you a template to copy. If you want one made for you right now, the free invoice generator builds it in your browser and saves it as a PDF.

A note before starting: what an invoice must legally show depends on where you trade, especially for sales tax, VAT or GST. Treat this as the practical baseline, and check the local rules with your accountant.

The fields, one by one

Who it is from

Your business name as it is registered, your address, and an email or phone number the customer can use with a question. If you are registered for sales tax, VAT or GST, your registration number usually belongs here too.

Who it is for

The customer's name and billing address. For a business customer, the name of the person or department who approves payment, and any purchase order number they gave you. An invoice sent to the wrong person is an invoice that waits.

A unique invoice number

Every invoice needs a number that is never reused, in a sequence you can follow, such as INV-1041, INV-1042. It is how you and the customer refer to it, and how your accountant keeps the books straight.

The dates

• Issue date: the day you send it.
• Due date: a real date, not "30 days". "Due by October 9" asks nothing of the customer; "net 30" asks them to count.

What you did

One line per item, in plain words, with its quantity, its unit price and its total. Name the outcome where you can: "Walnut cabinetry, supplied and fitted" beats "Joinery, 24 hours". If the invoice follows a quote, use the same wording so the customer can match them.

Tax

Show the tax rate and the tax amount, either per line or as a total, as the rules where you trade require. Make the difference between the amount before tax and the total obvious.

The totals

Subtotal, any discount, tax, and the total due, with the total due the most visible number on the page. For a stage invoice, show what the stage is and, ideally, what has been billed and paid so far.

How to pay

Every way the customer can pay, spelled out: a Pay now link, bank details, anything else you accept. The easier this section, the faster the money.

Terms and notes

Your payment terms in one or two sentences, including any late fee your agreed terms allow, and a thank-you. Keep it short; nobody reads a paragraph of small print on an invoice.

The template

Copy this structure into your own layout:

Stage invoices and deposits

For work billed in stages, each invoice should make the whole picture clear, not just its own amount:

• name the stage it covers, in the same words as the quote;
• show the contract total, what has been invoiced before, and what has been paid;
• credit the deposit against the right invoice, and say so;
• show what remains to be billed after this one.

A client who can see the running total never has to reconstruct it from old emails, and rarely queries a stage invoice as a result. Our article on deposits and milestone billing covers how to set the stages.

Mistakes that delay payment

• Vague lines. "Work as agreed" invites a question; a question invites a delay.
• No due date, or a term instead of a date.
• Missing payment details, or bank details only in an old email.
• The wrong recipient, especially at larger customers with an accounts department.
• Arithmetic errors. One wrong total and the whole invoice goes back for correction.
• Sending it late. An invoice sent two weeks after the job starts the clock two weeks late.

Wording for payment terms

Short, specific and agreed in advance works best. A few examples to adapt:

• "Payment is due within 7 days of the invoice date. Thank you for your business."
• "A deposit of 30% secures your start date and is credited against this invoice."
• "Invoices unpaid after the due date may incur late interest as set out in our terms."

Only include a late fee if the customer agreed to it on the quote, and check that it is lawful where you trade.

Invoice numbering that works

Pick a simple sequence and never break it. A prefix and a running number, such as INV-1041, is enough for most businesses. Some add the year, such as 2026-041. Avoid reusing numbers, skipping them without a record, or restarting the sequence without your accountant's agreement, because gaps and duplicates are exactly what an auditor asks about.

Sending the invoice

• Send it the day the work is done, while the job is fresh and the client is pleased.
• Send it to the right person, with the purchase order number if they gave you one.
• Put the essentials in the email itself: the amount, the due date and the Pay now link, so the client does not have to open an attachment to act.
• Keep a copy of exactly what was sent, and when.

Corrections and credit notes

Once an invoice has been sent, do not edit it or delete it. If something is wrong, issue a credit note that cancels all or part of it, then a new, correct invoice. The trail stays complete, your numbering stays unbroken, and your books match what the client received.

From template to automatic

A template helps the first time. After that, the work is in the routine: raising each invoice on time, sending it to the right person, reminding before and after the due date, and marking it paid. In grewray, an accepted quote becomes the invoice with every line carried over, each invoice carries a Pay now link and marks itself paid, reminders run on their own, and everything syncs with QuickBooks Online, Xero or Zoho Books. See invoicing and payments, and read how to get paid faster for the habits around the invoice.