The .tax file is the same for Mac and PC. If you mean to transfer carry over data into TurboTax online for 2020 then it is the same file either way and can be uploaded from either computer into online.
Also see:
https://ttlc.intuit.com/community/entering-importing/help/transfer-last-year-s-return-to-turbotax-fo...
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
