The QR digital receipt
Every receipt's QR opens a hosted copy of the bill on the guest's phone.
The printed receipt carries the restaurant's identity, tax registration number, full tax breakdown and a QR code. Scanning it opens the same bill on a phone — a snapshot taken at payment, so it stays correct even if the order changes later, and it stays available long after the visit. The guest can read it in English or Arabic and, where e-mail is available, send it to their inbox.
If the till could not reach the server at payment, the QR carries the invoice's tax details instead of a link.
The e-mailed copy says “Tax Invoice” (Saudi and Indian bills carry their own ZATCA or GST title) — or “Receipt” for a bill that charged no tax in a country with no VAT (Kuwait, Qatar), with no tax-number line unless one is set. On the hosted page, the tax QR box appears only when there is a QR to show — there is no empty box. A Saudi business invoice that ZATCA has not cleared yet keeps its box, with the message Not yet cleared by ZATCA - not a valid tax invoice until it is. Ask for the cleared copy.
Point customers to the QR instead of reprinting — it saves paper and they keep the bill.