What is hide my email used for?

You can use Hide My Email to create a random email address if you don't want to use your own email, for example to register on a website you might only want to use once. You will then receive emails at your normal email address - but when you do not want to use the service you have signed up for, you can simply delete your random email again.

That way, you avoid receiving advertisements and other things in your own email. and you avoid giving out your real email to someone who might later send you SPAM emails.

You can read more about Hide My Email here:

What is Hide My Email? - Apple Support