Invoice Rules UK: Legal Requirements & Best Practices
HMRC invoice rules for UK businesses. VAT invoices, credit notes, self-billing, and electronic invoicing.
When You Must Issue an Invoice
You must issue a VAT invoice when: • You're VAT-registered • You make a taxable supply to another VAT-registered business • The customer requests one
Timeline: within 30 days of the supply date (or payment date, whichever is earlier).
You don't need to issue VAT invoices for exempt supplies or to non-VAT-registered customers (though you may choose to).
Credit Notes
Issue a credit note when you need to: • Correct an error on an invoice • Give a refund or credit • Adjust the price after invoicing
Credit notes must reference the original invoice and include: • Unique credit note number • Date • Original invoice reference • Reason for the credit • Net amount, VAT, and gross amount of the credit
Electronic Invoicing
The UK has no mandatory e-invoicing format (unlike France or Italy). However: • MTD requires digital record-keeping • Peppol is gaining adoption for B2G transactions • PDF invoices sent by email are fully accepted • Consider structured formats for future-proofing
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