You will receive a notification email that your credit card will be expiring soon. You will need to update your payment method with your new card details before any upcoming payments are due. If your credit card details are not updated in time, you'll also receive email notifications about the failed payment once it is due.
A failed payment due to an expired credit card is handled the same as a general failed payment. You will have time to rectify the payment, but your account will also be subject to deletion if not paid in time.