alternative email address
I want to know how to add a non Apple email account to mail.
Question marked as
Top-ranking reply
To add a whole new Mail address - Add an email account to Mail on your Mac - Apple Support
Or if you mean an iCloud alias - Add and manage email aliases for iCloud Mail on iCloud.com – Apple Support
(I believe David McKinlay already answered you here - how do i add another email address - Apple Community)