Hi Chief,
In order to save a backup of your progress in the game, you need to use a Game Center account. It’s not mandatory, but it’s the only thing that will let you load up your village on another iOS device. This can be a life-saver if you ever lose your current phone, tablet or iPod.
Game Center only supports one game per account, and that you will need a different Game Center account for each new game you play on other devices. Also, each Game Center account requires a unique Apple ID.
To create a Game Center account, go to Settings > Game Center and log in with your Apple ID. Once you have created the Game Center account, you can launch Clash of Clans and your progress will automatically be linked to Game Center.