Your Apple ID is an account that lets you access all Apple services. Use your Apple ID to download apps from the App Store; access media in Apple Music, Apple Podcasts, Apple TV, and Apple Books; keep your content up to date across devices using iCloud; set up a Family Sharing group; and more.
You can also use your Apple ID to access other apps and websites (see Update account, security, and payment information. In Access your iCloud content on your Mac and Manage a Family Sharing group on Mac in the macOS User Guide.
Update account, security, and payment information. In Access your iCloud content on your Mac and Manage a Family Sharing group on Mac in the macOS User Guide.