Since iOS 13 you've had the option to use Sign in with Apple to register with any apps, websites or services that offer it. Basically it is like signing up for something using your Google or Facebook credentials, but it doesn't track and profile you like they do. If you have been using Sign in with Apple you can view and manage which of your apps and services are using it in your iPhone or iPad Settings. Here's how:
The ability to synch your Messages (as well as numerous other services) across multiple Apple devices is undoubtably a huge convenience, but also one that could lead to a serious breach of privacy. Obviously nobody wants their private messages accessible to friends, family and co-workers. If you are the type to have your text messages arrive on every Mac that you use, you might want to check which ones you are logged into, as you wouldn't want your messages popping up on a Mac that you share with a roommate, or on an iPad that you left at a friend's house.
For a limited time, Apple is offering a 10 percent bonus for adding funds to an Apple ID. When funds are added to your balance, this money can be used across Apple's online stores and services. For example, subscriptions to Apple TV+, Apple Arcade, or Apple Music can be paid from an Apple ID balance. Also included are purchases from the App Store, iTunes Store, Apple Books, and more.
Everything that's purchased from Apple using your Apple ID can be viewed in one consolidated list. To see apps, TV shows, subscriptions, books, and more, anyone with an Apple ID and an iPhone, iPad or iPod touch can head to Settings. Alternatively, purchases made with an Apple ID can be viewed from anywhere with a web browser.
Nothing is worse than forgetting an important password. Except maybe forgetting all of your sign in credentials completely. Without the email address associated with your Apple ID, the account cannot be accessed. The good news is Apple makes it possible to look up a lost Apple ID. In the worst case scenario, finding a forgotten Apple ID takes trial and error.