in the estimated tax section you can select to apply the entire overpayment to 2020. sometimes it's tricky with TT in that even though the overpayment shows up on the state return you still have to tell TT how much to apply
I think in the Estimate section is just to apply a refund from 2018 to the current year 2019.
To apply your federal refund to next year, enter it under
Federal Taxes Tab or Personal (Home & Business)
Other Tax Situations
Additional Tax Payments
Apply Refund to Next Year - Click the Start or Update button
To apply your state refund to next year, enter it under
State Taxes tab
And keep continuing and stepping through the interview about a dozen or more screens and it will finally ask how much you want to apply. It is probably one of the last questions in the state section.