you can transfer the xxx.tax2021 (no conversion from windows to mac necessary) (c:\users\user name\documents\turbotax folder to a thumb/flash drive and from there to the new computer. or even email it to yourself as an attachment. save to desktop of new computer so you know where it is.
Open TurboTax for Mac and choose File > New Tax Return . it will search for prior year file. if it doesn't find it you can browse to the desktop and select the file.
any pdf's of prior year returns should also be transferred.
see this link to make sure the iMAC meets minimum system requirements
https://ttlc.intuit.com/community/taxes/discussion/what-are-the-mac-system-requirements-for-turbotax...
