If you have an Apple ID that does not end in @icloud.comand you want an email that does end in @icloud.com, you have to create a NEW Apple ID in "Settings > Passwords & Accounts > Add Account > iCloud > Create a new Apple ID". Just don’t ever use it to purchase anything. It is just for email.
You do not have to have an @icloud.com email address, but it is recommended to have at least two different email accounts where one is the recovery email for the other and vice-versa. If you already have two different email addresses, you don’t have to create an @icloud.com email address.
John R Carter Sr