Adds a new payment card to the user’s account. The card may be saved for future transactions and can be set as the default payment method.
The ID of the user adding the card.
"user_12345"
The card number.
"4242424242424242"
Card expiry month (1-12).
12
Card expiry year (4-digit).
2027
Card CVC/CVV security code.
"123"
Whether this card should be set as the default payment method.
true