Do you know how to import mbox emails from On My Mac mail to iPad mail on iPad Pro?

This question, "Is there a way to import mbox emails from my Mac mail to ipad mail on my ipad Air??" has been asked in 2013 and I don't see any solution yet. Would you know?

I too have a number of emails stored in Mailboxes On My Mac and I would like these saved old emails from my iMac to be available on my iPad Pro for when I travel. Thanks!