18Docs

How to create a professional invoice

A clear, complete invoice gets you paid faster and looks professional. Whether you are a freelancer sending your first bill or a small business standardising your paperwork, the essentials are the same — and once you have them, generating the PDF takes a minute.

What every invoice must include

At minimum: the word ‘Invoice’ and a unique invoice number; your name or business and contact details; the client's details; the invoice date and a due date; an itemised list of what you are billing for with quantities and rates; the subtotal, any tax, and the total due; and clear payment instructions. Missing the invoice number or due date is the most common reason an invoice gets queried or paid late.

If you charge tax — GST, VAT or sales tax — show it as a separate line with the rate, and include any tax registration number you are required to display. For cross-border work, note the currency explicitly so there is no ambiguity.

Numbering and payment terms

Use sequential invoice numbers (for example INV-0001, INV-0002) so both you and your client can reference them and your records stay clean for accounting. Spell out payment terms — ‘due within 14 days’, accepted methods, and any late-payment note — rather than leaving them implied.

An invoice generator handles the layout and maths for you: you fill in the line items and it produces a tidy, consistent PDF with totals calculated, ready to send. Because it runs in your browser, your client and pricing details are never uploaded.

Tools for this

Frequently asked questions

What is the most important thing on an invoice?
A unique invoice number and a clear due date. They make the invoice easy to reference and set the expectation for when payment is due.
Do I need to show tax separately?
If you charge GST, VAT or sales tax, yes — show it as its own line with the rate, plus any tax registration number you must display.