Free invoice generator
What you get
A blank invoice opens in the app with the next number in your sequence already on it. Pick the client, add the lines, and it works out the tax and the total as you type. Download it as a PDF, print it, or send a link the client opens in any browser, with a Download button of their own and your payment details at the foot. Nothing is uploaded unless you send it: the document is written in a database inside your browser, and it is still there when the signal is not.
What an invoice has to carry
In the United Kingdom an invoice is a legal document with required contents, and the requirements are stricter once you are VAT registered. A plain invoice needs your business name and address, the customer's, a unique number, the date, a description of what was supplied, the amount, and how to pay. A VAT invoice adds your VAT number, the tax point, the rate applied to each line and the VAT itself as a separate figure. The generator puts every one of these on the sheet, and the guide to invoice contents goes through why each is there.
The number matters more than it looks
Invoice numbers have to be unique and, in practice, sequential. The app hands out the next number the moment an invoice is issued, not when it is started, so an abandoned draft does not burn one and leave a gap. If you number by job or by year, the number on any issued invoice can be changed by hand, and the change is recorded. Why a gap is a problem is worth five minutes before your first one.
Getting paid faster
Two things on the invoice do more for your cash flow than any reminder. Payment terms stated as a date rather than a phrase, since "net 30" is read by an accounts department as "thirty days from whenever we log it", and the date is not. And your bank details on the sheet, so nobody has to email you to ask. The generator prints both, and the guide to terms has the reasoning on what to set.