how to find apple id

Change an Apple ID on a Mac

All users should have their own Apple ID, which is tied not only to an iCloud account, Messages, FaceTime, App Store, iTunes, iBooks, and Passbook with ApplePay, but in new versions of Mac OS X an Apple ID can also be used to log into a Mac user account too. Because each Mac user should have their own unique Apple ID for their own devices, it can sometimes be necessary to change an Apple ID associated with an iOS device or, in this case, a Mac running MacOS X.

Remember, Macs support multiple user accounts with Mac OS X, and accordingly multiple Apple ID's can be used on a single computer with those different user accounts. For example, your personal Mac user account could use one Apple ID associated with your iCloud and iOS devices, while your spouses user account could use a completely different Apple ID that is associated with their iPhone. In fact, it's a really good idea to keep Apple ID's and user accounts separate, not only for privacy purposes, but so you don't have overlapping messages, FaceTime, Contacts, etc, but also so that you can have a much easier time preserving and restoring backups for your individual Apple devices. The ability to separate user accounts like this is one of the main differences between how Apple IDs can function on a Mac in MacOS versus iOS, where on the mobile side, only one ID can be used because there is no user account differentiation on an iPhone or iPad. Take advantage of this ability in Mac OS X, it's very helpful.

Changing an Apple ID in Mac OS X

To change the Apple ID / iCloud Account* associated with a specific Mac user account, you'll want to be logged into the user account you wish to change. Changing the associated Apple ID means logging out of the existing Apple account, and then logging into the new one. This is not difficult, but if you're looking for something labeled 'Apple ID' you won't find it, it's under "iCloud" instead:

Pull down the  Apple menu and go to "System Preferences"
Choose "Apple ID" or "iCloud" (depending on MacOS version)
Click the "Sign Out" button to log out of the existing Apple ID on that user account – note the message that logging out of that Apple ID may impact iCloud Drive documents and data, if you don't want to do that, don't log out, and instead use a different user account in Mac OS X

Sign out of an Apple ID in Mac OS X to change it

When iCloud finishes logging out of the Apple ID, the iCloud preference panel changes to a simple login screen
Log into the other Apple ID you wish to change to on the active Mac user account

For a new Mac user account that doesn't yet have an Apple ID, the option to create one is included in the System Preference panel for iCloud. You can also choose to create one on an iPhone or iPad, or through the Apple "My Apple ID" website here.

Remember, changing the iCloud and Apple ID will impact your logins to iTunes, App Store, Messages, FaceTime, Contacts, Calendar, and much more.

Apple ID

If you're wanting to use a different Apple ID for a friend, family member, roommate, a talented housecat, or another individual, you're better off creating a new user account in Mac OS X and logging into that other user account to sign specifically into the other Apple ID. That way you don't need to change an Apple ID and all associated aspects of it, like your iCloud data, Contacts, App Store details, cloud documents, and all else that is related.

Of course there are other reasons you may need to change Apple ID's on a Mac too, like accessing content outside of your region, on a foreign iTunes or App Store, for example.

In the ideal situation, each person will have their own unique Apple ID, and only one iCloud account / Apple ID (they are the same thing, though it is a technical possibility to have a separate iCloud account and Apple ID, it is really not recommended because it can cause a variety of hurdles and issues.). Unless you have a compelling reason to stray from that recommendation, try to use the same Apple ID on all of your personal Mac user accounts and iOS devices. Any other users of your Mac should have their own unique user account and they can use their own separate and unique Apple ID for their own Mac OS X user login and associated iOS devices too.