Under Payment Method, select Change.
Add a new payment method, or select an existing payment method. Make sure to include your billing address.
Finally, once you've entered the payment method details - including the billing address - select Use this payment method.
If you experience any issues updating your payment information, please visit pay.amazon.com/us/help for additional assistance.
Then, from your account page, select Payment options.
Here, you can add a new payment method, or update an existing payment method. To add a new payment method, under Add a New Payment Method, select Add a card.
Enter your information. Make sure the box for Use this card across all of Amazon is checked. Then select Add your card.
To update an existing payment method, select the card, then select Edit. If you'd like to use this card for your Sling TV bill, make sure to click Use this card across all Amazon.