iCloud: Apple ID
An Apple ID gives you access to the iTunes Store, the App Store, Apple Books, iCloud, FaceTime, and other Apple services. It consists of an email address (for example, firstname.lastname@example.org) and a password. To learn more about Apple ID, see the Apple ID Support page. To create one, go to the Apple ID account website.
Note: In some locations, you can use a phone number instead of an email address as your Apple ID. See the Apple Support article Use your mobile phone number as your Apple ID.
All of your purchases are tied to your Apple ID, and can’t be transferred to another Apple ID. If you make purchases on your iPad, iPhone, or another Mac, always sign in using the same Apple ID so you can see all of your store purchases on this Mac and download any available updates.
It’s recommended that you use the same Apple ID for all Apple services, including the iTunes Store, the App Store, and Apple Books. However, if you already use different Apple IDs for different services, you can continue to do so. See the “Use different Apple IDs for iCloud and iTunes” section on the Sign in with your Apple ID page.