"Can I transfer files to my Mac and will windows files transfer to Mac version 2020 software?"
Yes but, of course, you have to install a (desktop) version of TurboTax for Mac. Otherwise, your .tax2019 file will transfer to your Mac installation.
See https://ttlc.intuit.com/community/tax-data-file/help/how-do-i-transfer-last-year-s-return-into-the-t...
