Invoice Guides
An invoice never exists on its own. It fulfils a purchase order, creates a receivable, carries tax, falls due under payment terms, and — in a growing list of countries — must be issued in a regulated electronic format. These guides explain that surrounding world.
Looking for a specific document type instead? The invoice types hub explains 27 of them. Need a quick definition? Try the glossary. Just need to bill someone? The generator is free.
Documents & Paperwork
Every sale generates a chain of documents. A quote or estimate proposes the deal. A purchase order authorises it. An invoice requests payment for it. A delivery note travels with the goods, and a receipt proves the payment happened. Each document has one job, and most billing disputes trace back to two of them being confused.
Accounting
The moment you issue an invoice, it stops being a document and becomes an accounting event. It creates a receivable, it may recognise revenue, and it will eventually need to be matched against a payment.
- Accounts Receivable: The Money Your Invoices RepresentWhat AR is, how invoices create it, and how to keep it from quietly becoming bad debt.Read the guide
- Cash vs Accrual Accounting: When Does an Invoice Count?The two ways to answer "when did I earn this?" — and what each means for your invoices.Read the guide
- Bookkeeping Basics for People Who Send InvoicesThe minimum viable bookkeeping system for a freelancer or small business.Read the guide
- Double-Entry Bookkeeping: Why Every Invoice Touches Two AccountsDebits, credits, and what actually happens in the books when you issue an invoice.Read the guide
- Revenue Recognition: When Is the Money Actually Yours?Issuing an invoice and earning revenue are not the same event. Here is the difference.Read the guide
- The AR Aging Report: Reading the Age of Your Unpaid Invoices30, 60, 90 days: what the aging buckets mean and what to do about each.Read the guide
Compliance
Invoicing is regulated. What an invoice must contain, how long you must keep it, and — increasingly — the technical format it must be issued in are all set by law, and the law is moving fast: a growing list of countries now mandates structured e-invoicing for business-to-business sales.
- E-Invoicing Mandates: Who Must Switch, Where, and WhenStructured e-invoicing is becoming law across the EU and beyond. The map and the timeline.Read the guide
- What Makes an Invoice Legally Valid?The fields the law cares about, and how requirements differ by country.Read the guide
- How Long to Keep Invoices: Retention Rules by PurposeTax audits, warranties and disputes each set their own clock. Keep the longest one.Read the guide
- Electronic Signatures on Business DocumentsSimple, advanced and qualified signatures — and whether invoices need one at all.Read the guide
- Peppol: The Network Behind Modern E-InvoicingHow Peppol moves structured invoices between businesses, and who has to use it.Read the guide
Where to Go Next
Invoice types
Proforma, commercial, credit note, GST — 27 document types explained, each linked to a matching template.
Browse invoice typesGlossary
Short, precise definitions of invoicing and accounting terms — each one routed to the deeper read.
Browse the glossaryHow-to articles
Practical walkthroughs — making an invoice, chasing late payment, adding tax, numbering done right.
Browse the blog