To see user ID and transfer code, tap "Other" icon at the bottom of the screen. Then tap "Data Transfer".
User ID and transfer code pops up. Note them to play the game on another device.
Tap "Data Transfer" at the top of the start menu screen.
You will be asked to enter user ID and transfer code. By entering those codes, you can take your game data over.
Transfering game data
Naruto Uzumaki (Rasengan Mastered)