Although both Apple and Microsoft say it’s easy moving between their platforms, things aren’t as easy as they seem.
You can struggle for hours trying to move your data. I’ve tried conversion tools and some emails always fail. The best method is to take advantage of IMAP, which will let you store emails on a server, then download them again.
If your ISP doesn’t give you an IMAP account, there are Lots of webmail providers such as gmail can give you an IMAP account.
Once you’re set up, just drag the emails into the IMAP folder and they will upload to the server.
Now, just configure your new client and download the emails. Done!
If you are worried about privacy, you can download and install hmailserver, create an account on that and then just send the messages to your local server.