If the LLC was formed in January and was granted S-Corp as of January, you only need to file the 1120-S return.
In TurboTax Business you want to be sure to indicate you started on January 1st and that you closed the business in 2020 as well.
TurboTax Business will ask you questions about Form 2553, which is the S-Corp election you filed. You do not need to file it again with this return.
