Redeem Xbox codes on a computer by signing into your Microsoft account at Xbox.com, clicking redeem and entering the code, or redeem them directly through the Xbox One or Xbox 360 consoles, as of 2015. Connect the console to the Internet in order to redeem the codes on the device.
To redeem prepaid Xbox codes on the Xbox 360, turn on the device and press the center guide button. Find the games and apps section, and choose the option to redeem codes. From that screen, enter the code and follow the on-screen prompts to complete the redemption.
To redeem the codes on the Xbox One, go to the store from the home screen, and go to the games category. From that screen, choose the option to use a code. Alternatively, you can say "Xbox, use code." Sign in if you are prompted to, and hold the QR code to the Kinect sensor. If there is not a QR code, choose the option to enter the code manually, and then enter the code.
Xbox codes are usually 25 characters long and are found on cards purchased from retailers. Prepaid codes provide a way for users to make purchases on Xbox live without using a credit card.