Apple
You can connect your game to Apple from the game settings. Tap on the cogwheel at the top right of the screen, and then tap the Connect button. After that, tap the button with the text "Continue With Apple." Then follow the instructions given, and your account will be connected.

Once you have connected your game to your Apple account, your game progress will be saved to that account. If you ever need to reinstall the game or wish to play on another iOS device, you can restore your progress by connecting to the same account.

If you choose to disconnect your game from your Apple account manually, your progress will no longer be saved, and you will be unable to recover it if you reinstall the game

Facebook
You can connect your game to your Facebook account from the game settings. Please tap on the cogwheel at the top right of the screen, and then tap the Connect button with the Facebook icon on it. You will then be prompted to log in to your Facebook account.

Once you have connected your game to your Facebook account, your game progress will be saved to that account. If you ever need to reinstall the game or wish to play on more than one device, you can restore your progress by connecting to the same account.

If you choose to manually disconnect your game from your Facebook account, your progress will no longer be saved, and you will be unable to recover it if you reinstall the game.