The Store Credit section of your account dashboard lists amounts from returns and refunds that can be applied to future purchases. You can also redeem the value from a gift card.
To apply store credit during checkout:
Determine the amount of available store credit. During the Review & Payments step, the available amount appears under Store Credit.
To apply the amount to the order, tap Use Store Credit.
Use Store Credit
The order total is recalulated, and the amount of store credit that is applied appears in the Order Summary. Order Summary with Store Credit
When ready, tap Place Order.