If you're using the same TurboTax account (same username and password) that you used when filing your 2020 return, this "refund applied to next year's return" should automatically populate into your 2021 return. If it didn't, you can use the instructions I'm linking below to locate where to enter this 2020 refund applied to 2021 tax liability.
How do I get credit for a refund applied to 2021's taxes?
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
