Learn about the customer resource
For example, once you set a customer's
shipping.address, you can retrieve these values during later checkouts and display them as an available option to the storefront customer. This often helps expedite the checkout process.
Additionally, if customers want to save a reusable payment method for future use, you can attach the created payment source to their record. When that same customer later initiates a registered checkout, you can retrieve a list of applicable payment methods and then use this list to filter the customer's reusable sources before displaying them in your GUI.