I paid extra to file my 2019 State Tax return, but I don't see any place for my estimated taxes for 2020. How come?
In the California interview, on the screen with the heading "A few things before we wrap up your state taxes", look under subheading "Other forms", and click Start for Estimated Taxes for next year.
Otherwise, while doing your 2019 return, if TurboTax sees that you should pay estimated taxes to the IRS or to a state, it will generate 1040-ES (IRS) or 540-ES (California).
Note the numbers on these forms are suggestions - you don't have to use these numbers if you determine that other amounts (or no amounts at all) would be more appropriate. See the 540-ES instructions.
The answer provided is simplistic and wrong. Getting to the proper location to enter a request for 2020 California estimated taxes is complex and lengthy. Then when you finish with all of these complications, one (I) cannot find the 2020 540-ES forms that are supposed to be on my computer. Turbo Tax for 2019 has been a painful, complex, un-rewording application. I hope there are better solutions available next year - not necessarily by Turbo Tax.
It would be helpful if you actually pointed out what was wrong with my answer, so that I could correct it. Just saying that it is simplistic and wrong is not helpful to you, us, or anyone else.