What information must be on an invoice?
Most countries require certain information on every invoice for it to be valid for the buyer’s and seller’s records — and tax authorities require extra details on VAT/tax invoices. Here’s a clear checklist of what every invoice should contain, and the extras for VAT-registered businesses.
The invoice checklist
Who is selling
Your business name, address and contact.
Who is buying
The customer’s name and address.
When and what number
Issue date, due date and a unique invoice number.
What and how much
Itemised lines, subtotal, tax (if any) and the total.
Step by step (and the VAT/tax extras)
Add your business details
Name, address, contact and tax ID if registered.
Add the customer
Name and billing address.
Date and number it
Issue date, due date, unique invoice number.
Itemise the work
Each line: description, quantity, unit price, line total.
Show totals and payment terms
Subtotal, tax (with rate), total, and how to pay.
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Frequently asked questions
What is the minimum information a valid invoice needs?
A valid invoice should show: your business name and contact, the customer’s name, a unique invoice number, the issue and due dates, itemised lines with prices, the total, and how to pay. If you are tax-registered, add your tax/VAT number and show tax as a separate line.
What extra information goes on a VAT invoice?
A VAT/tax invoice usually needs to additionally show: your VAT registration number, the tax rate applied, the VAT amount as a separate line, and (in many countries) the customer’s VAT number for B2B sales.
Do invoices need a due date?
A due date isn’t always strictly required, but you should include one — it sets expectations and gives you a clear point to follow up if payment is late.
Can a hand-written invoice still be valid?
Yes, provided it contains the required information. The format matters less than the content; a clean printed/PDF invoice just looks more professional and gets paid faster.
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