How do I Type While In-Game?

So, basically I want to know how to type something while the game is running. So if I had a signup sheet and needed you to submit a username, how would I do that and how would I get the keyboard to pop up on a tablet? Should I just make a custom keyboard layout? Like have a sprite with the letter E for example and say when spr_E is clicked => set text: ""+e or something like that?

You can use a text box object, it automatically opens the virtual keyboard for you and you can choose if you want the field to be used for username/password/email input.