Email address
How can i delete an email address i no longer have
it wont let me
iPhone 8 Plus, iOS 12
Question marked as
Is this a regular email address or an email address that you have been using for your Apple ID?
If it is an email address in Mail, have you tried going to Settings/Passwords & Accounts to delete the email?
If an email address for your Apple ID, have you tried doing a name change?
Note the restrictions in the article.
What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.