As a guest player, meaning players who have not connected their game to Facebook or LINE, the game progress is saved to the phone's storage. That data is not transferable and may be deleted if the phone OS is reinstalled or if the game data is manually deleted.
If you choose to connect your game to a service like Facebook or LINE, you are no longer a guest account player and your progress will be moved and saved to the platform. automatically. Meanwhile, your guest account will no longer be available.