Invoicing guides

Short, practical answers to the questions that come up when you send invoices, whatever you use to make them.

What to put on an invoice: a plain checklist

The details every invoice needs so it gets approved and paid without a follow-up email, from your business name to payment instructions.

An estimate says what the work will probably cost, a quote fixes the price, and an invoice asks for payment. When to send each one.

Why 02/03/2026 means two different days depending on who reads it, and how to write invoice and due dates that are clear everywhere.

A simple invoice numbering system: sequential, unique and never reused. What to do about gaps, prefixes and estimates.