To change your Player Name and Avatar simply tap on the avatar located in the upper left side of the game screen. Once this is done, the Player Name can be changed by tapping your Player Name right under the Avatar icon. Type in a new on you’d like to use. Once you’re done making changes, tap save!
Avatar can be changed in the same menu as the Player Name by tapping your avatar in the game. A selection of avatars will be displayed, and there you can pick the one you like most.