Why am I being asked to provide further information (e.g. the payment purpose) when paying via QR code?

Depending on the solution selected by a merchant, they can include certain text fields (e.g. payment purpose) in the payment process and decide which fields are optional and which fields must be filled in by the buyer in order to complete the payment.

This can be helpful, for example, if a restaurant with a delivery service has printed the QR code on a flyer. This enables the merchant to allocate the payment to your order.