Can emails be moved from the Windows based eM Client to the Mac based eM Client?

If your account is setup as IMAP in both versions of eM Client, then you will have the same messages in both.

I have not seen the database structure of the Mac version, but I would think it is the same. You can try backup (Menu > File > Backup) on the Windows computer, and restore (Menu > File > Restore) on the Mac. I would be interested to hear if that worked.

Hello Gary - thank you for your reply. I haven’t purchased my Mac but will do so soon. My windows  account is set up as IMAP. Will get back to you in the next week or two.
Regards Perry

Using IMAP should be very easy Perry. Just setup the same account on the Mac when you get it, and all the messages should sync.