The 6-digit code on an Xbox is the console's unique serial number. This code can be found in different places depending on the type of Xbox you own. For Xbox One consoles, the serial number is located on the back of the device. Alternatively, you can find it in System > Settings > System > Console info. On an Xbox 360, it can be found either on a label near the network port or on the sticker that came with your system when it was first purchased. The code should begin with two letters followed by eight numbers (e.g., XY12345678).