> invoice to be a payment request — which makes issuing them after payment nonsensical Most EU countries use an accrual-based VAT system, where taxes are owed

> invoice to be a payment request — which makes issuing them after payment nonsensical Most EU countries use an accrual-based VAT system, where taxes are owed on any invoice issued, paid or unpaid. This makes issuing them before payment nonsensical, because you will end up paying taxes on invoices that will never be paid, thus ruining your business. A proforma invoice exists specifically for the purposes of quoting and requesting payment.