Once you create a new account a name will be assigned to you. You can edit this by tapping on the hamburger menu on the top right of the main screen and then tapping on the profile photo.
If you select the edit pencil tool you will be able to choose a new name!

Please keep in mind you can only do this for free three times. So pick wisely!  

If you have any requests or further questions feel free to reach out to us in the game and we will be happy to assist you!