Sorry---brokerages do not make past year information available for import to tax software. You should have imported it for the tax year before it was too late. Now the only thing you can do is enter the information manually. Only 2021 information can be imported. Get the statements from your brokerage and enter the data by hand.
And....a 2020 return cannot be prepared using the online software. Online is only for 2021 returns. You need the desktop software on a full PC or Mac in order to prepare a 2020 return, which must then be filed by mail.
**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.**