Written with people moving from Turkey in mind. The Portuguese rules still apply more broadly.
Paying by Multibanco Reference
When shopping online in Portugal, you will often see "Pagamento por Referência Multibanco". The merchant gives you an Entity (5 digits), Reference (9 digits), and Amount. You can pay this via your banking app or at any ATM.
It is extremely secure because you never share your card details with the website. It is the preferred payment method for utilities, taxes, and even Amazon purchases in Portugal.