It's a feature enabling you to transfer your account to another device.
Setting up account transfer has the benefit of allowing you to carry over your account if you change your device, or to recover it if you accidentally delete the app.
The account transfer process is different when transferring between the same or different operating systems.
Please refer to the following steps in the FAQ to transfer your data.
- Transfer from one Android device to another
- Transfer from one iOS device to another
- Transfer between different OS
*The option to connect to Google Play or the Game Center may not appear depending on your app settings.
If this occurs, please refer to the "Transfer to different OS" steps.