Digital 25-character product codes can be redeemed from the Store section of the Xbox Dashboard. This is the third section of the Dashboard, beneath the Home and Game Pass sections.

Enter the Store using the Xbox app, and then scroll down to the bottom of the left-hand menu, where you'll find the 'Redeem' button. Using this will open the 'Redeem a code' screen, where you can input your Xbox Series X code with the on-screen keyboard.