Free invoice generator, signed and ready to send

What makes an invoice valid

There is no single worldwide invoice format, but tax authorities agree on the core. In the UK, HMRC’s guidance says an invoice must show a unique identification number, your business name and address, the customer’s name and address, a clear description of what you are charging for, the date of supply and the date of the invoice, the amount(s) being charged, VAT if applicable, and the total owed. EU member states follow Article 226 of the VAT Directive, which also requires the supplier’s VAT number. In the US, the IRS does not prescribe an invoice layout, but it expects you to keep documents that support the income you report — invoices are the primary record for that.

Invoice Studio’s default layout covers all of those fields. If you are VAT- or GST-registered, put your registration number in the address box and set the tax rate in Totals.

Why sign an invoice?

A signature is rarely a legal requirement on an invoice, but it helps in three situations: a client’s accounts team that insists on “signed and stamped” paperwork (common with larger companies and in parts of Asia and the Middle East), a job where the invoice doubles as a delivery confirmation, and disputes, where a signed document shows who approved it. You can type a signature in one of three handwriting styles or draw it on the pad; either is stored only in your browser.

Numbering, due dates and “Paid”

Use one continuous sequence (INV-0001, INV-0002…) and never reuse a number, even for a cancelled invoice — issue a credit or a new invoice instead. Invoice Studio remembers the last number you exported and suggests the next one. Enter any amount already received in Already paid and the invoice switches its headline to Amount due.

Finished a job with a quote first? Build the quote, get it signed, then press Turn into: Invoice to carry every line across.