Is it possible to use several gift card codes while placing an order?
Starting from 2.9.0 extension version, the admin can set the maximum gift card codes qty to be applied in one order. The setting is located at Stores → Configuration → Amasty Extensions → Gift Card → Gift Card Account → Gift Card Code Qty Applied On Checkout.
It's also possible to leave the setting empty. In this case, the amount of codes is unlimited – the customer can add as many codes as they have. As soon as a code is added, the customer is able to add another one in the same field.
Depending on the settings, the gift cards can cover different product types, shipping, taxes, and extra fees (with Amasty Extra Fee extension installed).