I paid $3400 income tax already in March 2021. Where do I enter that on my 2020 return?

[TurboTaxSusan]

If this payment was for your 2020 taxes, please see this TurboTax FAQ to learn how: How do I enter instalment payments?            

If this payment was for your 2021 taxes, you will need to wait until you are preparing your 2021 tax return.