Your account is linked to your mobile device. As long as you are using the same device, you will be able to automatically login to your account.  

To prevent problems after changing devices or having to reinstall the game, we advise you to save your account by registering your email address.

The option to do so can be found in the game's setting menu, under "Save Account".

 

Important: Should you receive an error when registering your email address, make sure there is no space character added behind the email. This would result in an "Invalid Email Address" error, causing the email to not be saved.

Please also keep in mind that every email address can only be used once per game world/server. Therefore you need to use an address that is not registered to another account already.