Apple ID
When you first purchase an iPhone or iPad, you must create an Apple ID. This ID is essential for everything you do with Apple, including shopping in the iTunes or App Store, accessing iCloud services, using iMessage or FaceTime, and contacting Apple support. Your Apple ID is typically an email address, which can be your personal email or an email ending with @icloud.com (also used to access your iCloud Account).
You can add alternative Apple IDs or emails to your account. To see which emails are associated with your account, log in using your Apple ID and password. Once logged in, you can delete old email addresses that you no longer use and ensure no other emails have been added. You can also update passwords, security questions, and other contact information. Use a strong password that others cannot guess, and change it if you suspect someone else knows it. Read more tips about passwords.