rescue email

See here: About your Apple ID email addresses - Apple Support

Rescue email address

Having a rescue email address is optional but recommended. If you ever forget your security questions, you can use your rescue email address to reset them. If you don't have a rescue email address, you'll need to contact Apple Support for help. We’ll also send any account security-related notifications to your rescue email address.

Follow these steps to add or edit a rescue email address:

1. Sign in to your Apple ID account page.
2. Click Edit in the Security section. You might be asked to answer one or more security questions before you continue.
3. If you want to add a rescue email address:
   • Under Rescue Email, click Add an Email Address, then enter your rescue email address. We'll send a verification to that address. Didn't get the email?
   • Enter the verification code and click Verify.
4. If you want to edit a rescue email address:
   • Select Change Email Address under the address you want to edit, then enter the new address. We'll send a verification to that address. Didn't get the email?
   • Enter the verification code and click Verify.
5. If you want to delete a rescue email address, click next to the address.
   

If you use two-step verification or two-factor authentication, you have a notification email address, not a rescue email address. With two-factor authentication and two step verification, you don't need a rescue address. You can also use these steps to add or edit your notification email address.

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i need to change my rescue email

If you know your answers to your security questions you can log into the account on http://appleid.apple.com and change it : About your Apple ID email addresses - Apple Support

If you can't remember your answers and don't have access to your current rescue email address see the 'if you can't reset your security questions' on this page : If you forgot the answers to your Apple ID security questions - Apple Support