How to Create a Purchase Order: A 2026 Guide for UK SMEs
2026-05-12
A purchase order (PO) is the formal bridge between “someone needs something” and “finance can pay the invoice with confidence.” When it is missing or vague, accounts payable slows down, audit trails weaken, and three-way matching fails. This guide walks UK SMEs through how to create a purchase order that suppliers can fulfil and finance can defend.
For the wider workflow, read procurement to pay and accounts payable and accounts receivable for UK SMEs.
Before You Create the PO: Requisition and Approval
In mature processes, a PO is not the first document. A requisition captures the business need, budget line, and timing. Once approved, that requisition becomes the PO. Skipping this step is tempting in small teams, but it is where off-contract buying and coding errors start.
What approvers should verify
| Check | Why it matters |
|---|---|
| Budget availability | Prevents overspend surprises at month end |
| Supplier on approved list | Reduces fraud and off-contract pricing |
| Correct tax and coding | Avoids rework when the invoice arrives |
| Delivery or milestone clarity | Enables clean goods receipt or service sign-off |
If approvers only see an email thread, you do not have a control; you have a story finance cannot match to an invoice line.
The Core Fields Every Purchase Order Needs
Whether you use accounting software, a dedicated purchasing tool, or a controlled PDF template, the PO should answer six questions without ambiguity.
- Buyer identity – legal entity name, registered address, and contact for queries.
- Supplier identity – legal name, address, and supplier reference used in your master data.
- Line detail – description, quantity, unit of measure, unit price, and extended price.
- Commercial terms – payment terms, incoterms or delivery location if relevant, and any volume or validity limits.
- Dates – order date, required-by date, and PO validity window if prices are time-bound.
- Internal references – PO number, cost centre or project code, and requester name.
PO numbering and versioning
Use a single sequential PO number space per legal entity. If the commercial detail changes materially after issue, revoke or close the original PO and issue a new version rather than editing silently. Auditors and AP teams both prefer visible version history.
Issuing the PO to the Supplier
Send the PO through the channel your contract specifies—email, supplier portal, or EDI. Ask for written acknowledgement. For services, attach or reference the statement of work so receipt confirmation later has a clear baseline.
Common mistakes that break three-way matching
| Mistake | Typical consequence |
|---|---|
| PO raised after the invoice arrives | Weak audit trail; looks like post-hoc approval |
| Mismatched unit of measure | Quantity mismatch at invoice match |
| Missing tax treatment | VAT corrections delay payment |
| Informal side emails changing price | Dispute between procurement and AP |
A PO is a contract instruction, not a friendly note. Keep commercial changes on-document.
After the PO: Receipt and Invoice Linkage
Operations or the budget owner should confirm receipt or milestone completion. Accounts payable then matches PO, receipt, and invoice. If your team also collects customer payments by card or bank debit, keeping purchasing discipline indirectly protects cash flow; see credit card processing fees and online payment security for related finance controls.
Practical Checklist to Create a Purchase Order Today
- Confirm the requisition is approved and budgeted.
- Select the correct supplier record from master data (avoid one-off free-text duplicates).
- Build line-level detail with clear quantities and prices.
- Apply payment terms consistent with the supplier contract.
- Generate the PO number and issue to the supplier with a clear request for acknowledgement.
- Store the PO where AP can retrieve it without searching inboxes.
When approved invoices are ready for bank execution, ConversorSEPA converts Excel, CSV, or JSON into valid SEPA XML so the payment stage stays as controlled as the PO stage.
Frequently Asked Questions
- What is the difference between a requisition and a purchase order?
- A requisition is an internal request that captures need, budget, and timing. A purchase order is the formal external commitment to the supplier with line-level commercial detail. Approving a requisition first prevents off-contract buying and gives finance a clean audit trail before money is committed.
- Which fields must every purchase order include?
- At minimum include buyer and supplier identity, line descriptions with quantities and prices, payment and delivery terms, tax treatment, dates, and a unique PO number tied to your entity. Also record the internal requester and coding so accounts payable can match invoices quickly.
- Why do post-dated purchase orders cause problems?
- When a PO is created only after an invoice arrives, auditors and AP teams cannot prove that commercial terms were agreed before the liability arose. That weakens control narratives and slows approvals. Issue POs before supplier performance where possible, or use documented change orders when scope shifts.
- How does a purchase order help three-way matching?
- Three-way matching compares purchase order, receipt or service confirmation, and supplier invoice. A complete PO gives AP a baseline for quantities, prices, and tax so discrepancies route back to procurement or operations instead of stalling in finance with unclear ownership.
