You can add a new credit card from the Settings panel of the Gelato Dashboard. Simply select Settings > Payment method and add a new card. Here you can also see what other payment methods are already stored and modify them if needed.
Alternatively, you can also add a credit card during the checkout if you are placing manual orders via the Gelato Dashboard.
Note: We need this info to be able to process your orders and we will not charge you anything unless you place an actual order.