Purchase order: Meaning, Sources and Supplier Questions

Short answer: A purchase order is a document a buyer sends a supplier to order goods or services. It lists what is wanted, in what quantity and at what price. It usually becomes binding when the supplier accepts it.

Not legal, customs or tax advice. General information only; check duties, documents and contract terms with your customs broker or adviser.

What two sources say about Purchase order

Source page	Publisher	What the page says
Purchase order	Wikipedia	Defines a purchase order as a commercial document a buyer sends a seller specifying the products or services, quantities and agreed prices. Says it does not by itself create a contract, and acceptance by the seller does.
What is a Purchase Order (PO)?	Razorpay	Describes a purchase order as a formal document a buyer sends a supplier listing quantity, price and expected delivery. Says it becomes binding when the supplier accepts and that the supplier invoices afterwards.

Key points

The buyer issues the purchase order to the seller. [1, 2]
It lists goods or services, quantity, price and expected delivery. [1, 2]
It may also include payment terms and shipping instructions. [1]
It becomes binding when the supplier accepts it. [1, 2]
The supplier may negotiate changes before accepting. [2]
Some buyers return invoices that lack a purchase order number. [1]

Purchase order compared with Invoice

Aspect	Purchase order	Invoice	Source
Who issues it	The buyer.	The seller.	[2]
When	Before delivery.	After delivery, to request payment.	[2]
Effect	Sets up the order and binds once accepted.	Triggers payment.	[1, 2]
Link	Its number is used to match invoices.	May be returned unpaid if it lacks a PO number.	[1]

Where sources differ

Wikipedia says a purchase order alone does not create a contract and also says such orders are contracts by nature under certain laws; legal effect varies by law.

Questions to ask a supplier about Purchase order

[ ] How do you confirm acceptance of a purchase order?
[ ] Which terms and conditions apply to my purchase order?
[ ] Can changes be made after the order is accepted?
[ ] Do you need a PO number on every invoice and shipping document?
[ ] What details must the order show before you start?

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Sources: [1] Wikipedia, fetched 2026-11-12; [2] Razorpay, fetched 2026-11-12. As of 2026-11-12. General information, not legal, customs or tax advice. Wording is paraphrased from the pages linked; your written quote and contract govern.