An invoice is a written request for payment. It tells your client what they bought, what it cost and how and when to pay. A good one answers every question the client might have, so the only thing left for them to do is pay it.
The parts of an invoice
A title and a number
Call the document “Invoice” and give it a number nobody else on your books shares. The number is how you and your client will refer to it from now on, in emails, bank references and your accounts. See how to number invoices.
Who it is from
Your business name, address, email and phone number. Add your tax registration number if you have one. If you trade under a business name as a sole trader, include your own name as well.
Who it is for
The client’s name and address. For a company, use its full name and send the invoice to the person or department that pays bills, which is often not the person who hired you. Ask at the start who that is.
Dates
Every invoice has an issue date. Add the date payment is due as an actual date. “Due 19 October” is harder to misread than “14 days”.
What you are charging for
One line for each thing, with a quantity, a price per unit and an amount. Write descriptions for someone who was not there: “Replaced kitchen tap and isolating valves” rather than “Plumbing work”. Clear descriptions get paid faster because nobody has to ask what they mean.
The total
Show the subtotal, any discount, any tax as its own line, and the total due. If you are not registered to charge tax, leave it out altogether.
How to pay
Your bank details or a payment link, and the reference you would like used, which is normally the invoice number.
When to send it
Send the invoice as soon as the work is done or the goods are delivered. The payment clock starts when the client receives it, so each day you wait is a day added to when you get paid. For long jobs, agree in advance to invoice at stages or monthly.
How to send it
Email a PDF. It looks the same on every device and cannot be changed by accident. Put the invoice number and amount in the subject line, for example “Invoice INV-0042 for £480, due 19 October”, so it can be found again.
If it is not paid on time
Most late payment is disorganisation, not refusal. Send a short, polite reminder the day after the due date with the invoice attached again. If that does not work, phone. Keep a note of what was said and when.
The Your invoices list on this site shows which invoices are overdue each time you visit.
Make one now
The invoice generator has a box for each of the parts above and works the totals out for you.