Check the American Express gift card balance before using it
Add the gift card as a payment method on Amazon if Amazon accepts it in your region
Go to Amazon checkout and select the gift card as the payment option
If Amazon does not accept it directly, add the card to your Amazon account as a credit/debit card
Use the gift card for purchases up to its available balance
If the order total is higher than the gift card balance, use another payment method for the remaining amount
Make sure the billing address matches the information associated with the gift card if required
If the card is declined, verify the card number, expiration date, and CVV
If the card still does not work, contact American Express customer support or Amazon support