You have to go to puzzle palace and at the top right hand corner it says new username click on it then chande your username!
How Do You Change Your User Name On Moshi Monsters?
You can't change your user name only your password. If you want a new username you need to adopt a new monster.
You can't change your user name
Go onto edit my account at the top of your room click on your name at the top and it will come up with old password and new password then it will say confirm new password