If the Apple ID can be unbound after being bound to the bank card, please refer to the following as an example:

For example, after logging in to the account in Apple mobile phone or iTunes, your account number will be displayed in the upper right corner, click the drop-down triangle on the right side of the account number and click "Account", then you will be asked to enter the password again. Enter the account information, where you can modify the payment information, choose to bind (or unbind) the credit card, and view the purchase record. For the users who bind the credit card for the first time, please note that the credit card must be a dual-currency credit card, and the "overseas payment function" must be enabled. The latest bank card payment is simpler, which is the familiar online banking payment.

click modify in the payment method to unbind the credit card.