In the payment methods tab, you'll find the current method of payment along with the current billing address. However, this is not the same as the shipping address. You would edit the address in this section if your billing address has changed.

Note: Your billing address is not the same as the shipping address. Refer to Update Shipping Address to change your shipping information.
If you’d like to edit the payment method assigned to a specific address profile you can do so via the subscriptions tab by editing your existing subscription. This is also where you can adjust the email on file for that subscription. 
Note: If you signed up using PayPal and want to change your payment method in PayPal, you may be able to edit the payment method in your PayPal settings. Otherwise, you need to cancel the subscription and start a new subscription via the checkout.  You cannot make changes for a prepaid subscription as this payment has already been made.