you did NOT CONVERT a C-corp to a multimember LLC in 2020 (a partnership/or S-Corp ). You liquidated the C-Corp and used its assets to form the LLC. you should file 2 returns one for the C corp as final and one for the LLC - 1065 or 1120S. There can be significant tax consequences of liquidating the C-corp. there are tax issues if the net worth of the LLC was negative when the assets/liabilities from the C corp were contributed to the LLC.
that's why Turbotax may be starting out with a C Corp return. if you did not do things properly in 2020 see a tax pro. things may need to be corrected.
there is always the possibility that nothing changes (unlikely) but if you are not filing 2 returns for 2020 you may be doing something wrong. the rare exception would be conversion 1 second after midnight on 12/31/2019 but then the 2019 C corp should have been marked final. it should have been liquidated on12/31 and the tax consequences of the liquidation should have been reported on the stockholders' returns if the C-corp conducted activity in 2020 including liquidating it needs to file its 2020 own return
