To redeem a Hotels.com gift card, one must first ensure that they have an account on the Hotels.com website or mobile app. Once the account is created or logged in, the user should navigate to the payment section during the booking process. There, they will find an option to enter the gift card code. It is usually labeled as "Gift Card" or "Promo Code." One must input the card number and any required security information exactly as it appears on the card. After entering the details, the user should click "Apply" to see the discount reflected in the booking total. If the value of the gift card exceeds the cost of the reservation, the remaining balance can often be used for future bookings. It is advisable to check the terms and conditions of the gift card, as certain restrictions may apply. For further assistance, users can refer to the relevant section on the Hotels.com website.