Business & farm

Report the sale in the Investment Income section of TurboTax -  see Where do I enter the sale of a second home, an inherited home, or land on my 2020 taxes? for instructions on both TurboTax Online or TurboTax Desktop versions of the program.

Yes, you can allocate the proceeds (and capital gains) in whatever proportions reflect the actual ownership. One person can report 60% of the proceeds and 60% of the cost basis on their return, and the other can report the remaining 40% (proceeds and cost basis) on their return.  Here are some sample screenshots to show what you will see in the interview.