Minecraft wiki entry for Player, associated text: In Bedrock Edition, usernames chosen in-game must be 3–32 characters. Users can choose a username and change it unlimited times from Settings -> General -> Profile. Alternatively, users that sign in with a Microsoft account will have the username set to match their Gamertag. Gamertags can be modified on the Choose your new gamertag page of xbox.com for a fee of $9.99 USD except if changing from the gamertag generated upon account creation [5]