Your Apple ID is the key that opens the door to all of Apple’s services. You use it to sign into iCloud, where you manage email, calendars, contacts, and more. You use it for purchases from Apple on the iTunes Store, or on App Stores. And you also use it to sign into Messages and FaceTime, to communicate with friends and family.
Since this single combination of a user name and password is so important to users of Apple devices, managing your Apple ID is important, Read more