Are you using the 2021 CD/download software? You cannot use online TurboTax for a 2021 return. Only a 2023 return can be prepared using online.
To enter the estimated tax paid:
Go to Federal>Deductions and Credits>Estimates and Other Taxes Paid>Other Income Taxes
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**