AppleID with additional email address different than one assigned with AppleId
If I use an additional email address under my existing AppleID will the Mail Icon on my new MacBook Pro still show emails from my existing email address as well as the additional new email address? My goal is to use the additional new email address but with the existing AppleID. I still have the need to access the old email account using my older MacBookPro. I also have an iPad and an iPhone11 Pro that I want to be able to just access email through the new email address as well.
MacBook Pro 15″, macOS 10.14