Hello,


you can develop a custom payment step or add the field to one of current steps. You can find the path of their controls in:

CMSDesk -> Tools -> E-commerce -> Configuration -> Store settings -> Checkout process -> edit -> Control path

You can store the needful data in CartItemCustomData field of shopping cart item object (system table). It is the built-in field for custom data. It saves the value to OrderItemCustomData automatically and stores it in database.



Best regards,
Helena Grulichova