I use the Mail app in macOS High Sierra. I want to make a backup copy of my emails that I could store on external hard drives and then “drag and drop” back into the Mail app in the future should I ever need to access theme again. After I have backups of these emails, I want to delete them from the server they are stored on that Mail accesses them from. Is it possible to do this? Ideally, I’d like to be able to save all emails from one account (iCloud, Gmail, my personal website hosting) into each their own archive file containing all of the emails for one account. Is that possible? Thanks for any help! Really unsure of how to do this.