[header] How to use an american express gift card [title] Call customer service to activate the card if you bought the card yourself. [step] If you have all of the purchase information for your gift card, you can call american express directly to register the card. Call 1-877-297-4438 to speak with an american express customer service agent. 
You'll need to provide your name, billing address, and some information off the receipt (if you have it). [substeps] First, you'll enter the card information (the 16-digit card number and the 4-digit security code) through the automated system.