In Turbotax, you enter interest income at a 1099-INT screen, even if you didn't get a 1099-INT from the payer (Robinhood).

In TurboTax (TT), enter at:
- Federal Taxes tab 

 - Wages & Income

Scroll down to:

-Interest & Dividends

  -Interest on a 1099-INT.  Click Start. If you previously entered a 1099-INT, click Update. On the next screen you will get a interest summary. Click *add interest income*

These days, most investment firms issue "Consolidated 1099" forms showing interest, dividends and sales. Interest under $10 is sometimes omitted, but technically must still be reported.