Can you open your return? As long as you have not Efiled or mailed the return, you can go back in and make changes. Please see the below steps:
In TurboTax Online, sign in to your account.
Select Tax Home in the left menu.
Scroll down to Your tax returns & documents.
Select 2020, and then select Add a State (you're not actually adding a state, this just gets you back into your return so you can make changes).
Enter a 1099R under
Federal Taxes on left
Wages & Income at the top
Then scroll way down to Retirement Plans and Social Security
Then IRA, 401(k), Pension Plans (1099R) – Click Start
If you are filing a Joint return be sure to pick which person it is for.
It's just as fast and easier to manually enter your W2 or 1099. Don't type the bank name or try to import it.
At the bottom pick - Change How I enter my Form
Then on the next screen pick - I'll Type it in Myself
Enter a 1099-Int under
Federal
Wages & Income
Interest and Dividends
Interest on 1099-INT - Click the Start or Update button