What if I can’t sign in to my Apple Account?
If you can’t remember your email, phone number, or password for your Apple Account, you may be able to recover it using another Apple device where you’re already signed in, like an iPhone or another Mac. If you don’t have another Apple device, or you don’t have access to those devices, you can try to contact Apple Support for more options.
If you’re having trouble signing in to your Apple Account when setting up your Mac, you can skip this step and try to sign in later. However, it’s recommended that you don’t create a new Apple Account if you already have one.
If you need more help, see the Apple Support article If you forgot your Apple Account password.