Why Icloudmail uses a non existing email..?
I changed email adress 10 years ago, still Icloud refuses to delete old , or non existing Icloud email, how to delete old icloud email to existing one..?
iMac 24″, macOS 14.1
See the article Add and manage email aliases for iCloud Mail on iCloud.com - Apple Support
You cannot delete or turn off a primary iCloud Mail address. You cannot use an alias to create a separate Apple ID, and an email alias cannot be converted to a primary iCloud Mail address.