Redeem your gift card or code
The easiest way to redeem a gift card or code is by visiting microsoft.com/redeem. If you or your family have multiple Microsoft accounts, make sure you're signed in to the one to which you want to apply the gift card or code. Then enter the 25-character code, select Next, and follow the instructions on the screen.
See Find your downloads and product keys for more info about downloading and installing apps and games.