Invoice vs receipt vs estimate vs purchase order

These four documents show up at different points of a sale, and they're easy to mix up. Here's what each one is, who sends it, and when — plus a free generator for each.

Quick reference

Document	Who sends it	When	Purpose
Estimate / quote	Seller → buyer	Before the work	Propose a price to win the job
Purchase order	Buyer → seller	To place the order	Formally commit to buy at agreed terms
Invoice	Seller → buyer	After the work	Request payment
Receipt	Seller → buyer	After payment	Confirm payment was received

Estimate / quote — a non-binding proposal of what a job will cost, sent before any work or commitment. "Quote" often implies a firmer, fixed price; "estimate" implies an approximation. Make an estimate →

Purchase order (PO) — the buyer's formal order to the seller, listing items, quantities, and agreed prices. It commits the buyer and gives both sides a reference number. Make a purchase order →

Invoice — the seller's request for payment after delivering goods or services, with amounts, due date, and terms. The core document freelancers and businesses send to get paid. Make an invoice →

Receipt — proof that payment was received, issued after the invoice is paid. The buyer keeps it for their records. Make a receipt →

How they flow together

A typical sale: the seller sends an estimate → the buyer approves and issues a purchase order → the work is done and the seller sends an invoice → the buyer pays → the seller issues a receipt. Not every sale uses all four — a quick freelance gig might be just an invoice and a receipt — but knowing the role of each keeps your paperwork (and your cash flow) clean.

Open the free invoice generator →