You don't. Unless you need to change something that carried over from 2019. What did they change? You can't update the 2019 return.
The extra federal tax that you had to pay is not deductible so there is no place to enter it on your 2020 tax return.
Thank you. I mistakenly inputted withheld taxes on the line with my extension. Thus, it showed I paid double the taxes. I didn't pay that so the IRS deducted it and I owed them the money. Turbotax's extension is very confusing. You have to really look for it and figure it out. I mail my extensions, so I have to find "Payment with Extensions" and then input $0.00. I thought Turbotax asked me when I started my 2020 return if the IRS had changed anything on my prior year's return; I thought I answered yes. But then, nothing happened and I can't find it again.
Thank you. Yes, I thought Turbotax wanted to know so it could note it on my 2019 tax return information since every year they bring forward prior year information. Further, my state return asked me if I wanted to file an extension for 2020, which I had already indicated I had filed when doing my federal return. Thus, that suggests that Turbotax is not accurately recalling the information placed on the federal return.