If you can't enter character's name in the game, then you need to download and install a keyboard from Google which is called Gboard (Download). Then launch the application Gboard and use the prompts to perform the necessary settings. After you finish setting up the keyboard, start the game again, in which you could not enter the name, and try again. If after everything you've done you have problems with entering of your name, then check out the ways to solve them in Gboard FAQ section (to follow).