Always
These fields prevent 80% of “we never got it” and “finance can’t pay this” loops.
- Your legal/trading name and contact email
- Client name and billing address
- Unique invoice number and issue date
- Description of work + line amounts
- Currency, total, and due date
- Payment method: bank details and/or pay link
By market
UK/NI often need sort code + account number and UK VAT treatment when registered. ROI commonly needs IBAN/BIC and Irish VAT when registered. If you are not VAT-registered, say so simply rather than inventing a number.
Optional but strong
Payment terms in days, PO number, and a one-line late-payment reference appropriate to the contract’s jurisdiction. Keep templates boring — boring gets paid.