A purchase order (PO) is a buyer-issued record describing a proposed purchase: the supplier, items, quantities, units, prices, delivery requirements and applicable terms. Its reference helps connect supplier acceptance, later changes, receipts and invoices.
A PO is useful when several people need a shared record of what was requested and agreed. It is not proof that goods shipped, arrived or were approved for payment.
Purchase order versus invoice and sales order
| Record | Usually created by | Main purpose |
|---|---|---|
| Purchase order | Buyer | Specify the proposed purchase and retain the authorized commitment |
| Sales order | Supplier | Record the customer's order in the supplier's process |
| Packing slip | Supplier | Describe the contents of a shipment |
| Goods received note | Receiving team | Record the actual delivery and exceptions |
| Invoice | Supplier | Request payment under the agreed terms |
Keep the references linked, but do not assume the documents have identical quantities or dates. A supplier may accept only part of a PO. An invoice may cover a deposit, one delivery or several deliveries. Invoice timing does not establish physical receipt.
Is a purchase order legally binding?
The label alone does not answer that question. Contract formation depends on the document terms, existing agreements, acceptance and applicable law. A message acknowledging receipt of a document is not necessarily acceptance of every commercial term.
For example, the US model UCC §2-206 addresses acceptance of an order through a promise to ship or shipment, subject to its conditions. That is not a universal rule that every PO becomes binding only when a supplier clicks “acknowledge.” Use the business's approved terms and retain the relevant acceptance evidence.
What information belongs on a PO?
Include enough detail for the supplier, receiver and finance team to identify the same purchase:
- Reference and version: PO number, issue date, buyer and authorized contact.
- Supplier and destination: supplier identity, delivery location and contact details.
- Line items: product identifier, specification, quantity, purchase unit and unit price.
- Delivery: requested date or schedule, with confirmation recorded separately.
- Commercial terms: currency, freight, tax treatment, discounts, payment terms and relevant agreement references.
- Instructions: approved substitutions, packaging or other requirements specific to the order.
Show which charges are confirmed and which remain estimates. A requested date is not a supplier promise. A PO total is not automatically the remaining unpaid commitment after partial invoices, credits or cancellations.
Worked example: 24 cases, two deliveries
A fictional retailer orders 24 cases at $30 per case, for a goods subtotal of $720, excluding freight and tax. The supplier offers 16 cases on Tuesday and eight on Friday.
The buyer should retain the original request and the accepted delivery schedule. When 16 cases arrive Tuesday, the receipt records 16, and eight remain due. If each case contains six units, the delivery represents 96 units before any damage or acceptance exception.
An invoice for the first 16 cases has a goods subtotal of $480. It can be reviewed against that delivery and the applicable payment terms; it does not necessarily have to wait for the Friday shipment. Oracle's receipt-matching documentation provides an example of software supporting payment for partial shipments.
If the supplier later proposes a price change for the remaining cases, keep that proposal separate from an approved revision. Update the commitment only through the authorized review process.
The lifecycle is not always a straight line
A practical workflow distinguishes draft, sent, supplier response, accepted change, shipment, receipt, invoice review and closure. Some steps repeat, overlap or happen per line rather than for the whole order.
A purchase can have several receipts and invoices. A canceled balance can close without being received. Financial settlement may continue after operational closure. Agree what each status means in your process so “closed” is not mistaken for “paid” or “fully delivered.”
A living purchase order keeps the original request, reviewed changes and later evidence together. This helps another operator understand the current commitment without erasing its history. It does not remove the need to count deliveries or authorize payment.
When is a PO useful?
Recurring supplier orders, multiple delivery locations, planned purchases and orders with detailed specifications often benefit from a consistent PO record. The business should define when a PO is required and how exceptions are documented.
Other approved records may support card purchases, subscriptions or emergency buys. The absence of a PO does not mean there is no purchase evidence, and the presence of one does not prove the purchase was authorized correctly.
If you need a single document, use the free purchase order generator. If the problem is managing changed commitments, partial receipts and follow-up across recurring orders, evaluate LineNow purchase order software with one actual supplier cycle.