Standard accounting practices require that invoices/receipts have sequential numbers. So it has to be integer, or some kid of sequential alphanumeric. Even if

Standard accounting practices require that invoices/receipts have sequential numbers. So it has to be integer, or some kid of sequential alphanumeric. Even if one uses UUID as primary key, it should have separate invoice_no (in whatever formatting they require such as 2023/001, or 1001,1002...) which is the human readable and referenced number. This is especially important if you are developing a multi-tenant system where the invoice number, say 2023/001, may exist for more than one tenant.