Hi Stumbler! Nurse Joy here to assist you with any Account related FAQs 📒  
This is where you can set up different settings and preferences. These differ depending on the platform you’re on (iOS, Steam, Android), but these mostly range from volume, graphics, button layout/configuration, language, and server region   

For mobile devices, you can link your account to Facebook, Apple, or Google Play to secure your progress and play on a different mobile device. Do note though that cross-platform (iOS - Android) login is only possible if linked through Facebook.  PC users have their accounts bound to Steam automatically and won’t be able to play on mobile.
Since the game’s readily available across different countries, several languages and regions are available to choose. Here you can see the list of languages available as well as the regions you can play in.
Selecting a language you’re unfamiliar with might get you lost in the game.
Choosing a region far from your own may also affect ping. Best to leave them as it is, unless you know what you’re doing!
Always a joy to help!