How to use Mac.com email as primary

I’ve used Macs for many years. I started with a Mac.com address. I could not use the address when iCloud started so I used my yahoo.com address as a primary for Apple management. I still receive email on my Mac.com address on my iPad but I can’t get it to work on my Mac mini and new Airbook.

Is there a procedure to allow me to use the address on the other devices. Most of my email comes from that Mac.com address.