How to write an invoice.
Writing an invoice is straightforward once you know the parts. A clear invoice gets you paid faster and looks professional. This guide covers everything an invoice should contain, in order, with an example — and you can build one free in invoice44 in under a minute.
What every invoice needs
Your details & logo
Business name, contact and tax ID if registered.
Client details
Who you are billing, with their address.
Number & dates
A unique invoice number, issue date and due date.
Itemised lines & total
Each item with price, plus subtotal, tax and total.
Step by step
Add your business details
Name, logo, contact and tax ID.
Add the client
Their name and billing address.
Number and date it
Unique number, issue date and payment due date.
List the work
Each item or service, with quantity and price.
Total and add terms
Subtotal, tax, total, and how to pay.
Ready to bill? Open invoice44 — free, no signup, works offline.
Frequently asked questions
What should an invoice include?
An invoice should include your business details and logo, the client’s details, a unique invoice number, the issue and due dates, itemised lines with prices, the subtotal, any tax, the total, and your payment details and terms.
Do I need to be a registered business to invoice?
No. Sole traders and individuals can invoice using their own name and contact details. If you are tax-registered, add your tax ID; if not, you simply leave it off.
How do I make my invoice look professional?
Add your logo, use clear itemised lines, include a unique number and dates, and state payment terms. invoice44’s templates handle the layout for you.
What payment details should I include?
Include how you want to be paid — bank transfer details, a payment link or accepted methods — plus your terms (e.g. Net 14) and any late-payment policy.
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