No experience of Apple email but it looks to be IMAP so will work OK.
If you have lots of POP emails on your PC and folders in your email program with saved emails then I use emclient as it imports from just about anything.
https://www.emclient.com/
Free version is all you need as works for 30 days. It is a great program as an alternative to outlook for long term use.
Steps:
1. Save a backup before starting just in case.
2. Import email into emclient, it will also import the account server settings usually.
3. When you are happy emclient has everything from your POP emails and saved email folders disable that account in emclient settings so it stops receiving mail on that account, the emails will still be in the program so are safe as they where pop emails and are in a local folder tree.
4. Force emclient to save a backup so you have a copy, I change the backup quantity to 5 versions so you have a few revisions.
5. Add a new Imap account with the server settings you use.
6. When this new Imap account is working you can copy or move emails from the old email local inbox folders into the IMAP inbox, they will upload and may take a while.
Also move the saved email folders by dropping them onto the IMAP email account or right click and 'move' and they will start to upload.
If there are thousands of emails uploading will take awhile if you are on a slow upload connection and if your provider rate limits uploads.
7.Once you are happy that everything is in your emclient program IMAP folders then you can add the email account as IMAP to apple mail and everything will synchronise.
If you are using a cheap provider such as a budget website host then consider something higher quality such as
https://mxroute.com/ great for IMAP email and doesn't cost much.
Always best to have email hosting in a separate account than your website host.
There are often great promotions at Mxroute.
Good luck.