Step by step
Identify the invoice
Use a unique sequential reference and show both the invoice date and the supply date. Keep the same reference in your records.
Identify both parties
Include your trading details and contact information plus the customer name and address. Sole traders and limited companies have additional naming rules.
Describe the charge
Use a clear line for each product, service or milestone. Show quantity or scope, price, discounts, VAT where applicable, and the total owed.
Make payment unambiguous
State the due date, accepted payment method and payment reference. Check purchase-order requirements before sending.
Ready-to-use checklist
- Unique invoice number
- Supplier and customer details
- Supply date and invoice date
- Clear description and amounts
- VAT information if applicable
- Total, due date and payment reference
Common problems
The client needs a purchase order
Do not invent one. Ask the authorised contact for the correct PO and billing address.
The invoice is disputed
Separate scope, price and completion evidence; respond in writing and issue a credit note rather than silently editing an issued invoice.
UK sources and scope
Checked 27 September 2026. Details may vary by nation, provider and circumstances; follow the linked official or specialist source for the current position.