You can go back into your return to change to e-file.  Somehow the program might have thought you mailed in your return.

How do I change from mail to e-file in TurboTax Online?

1. In TurboTax Online, sign into your account.
2. Select Tax Home in the left menu.
3. Scroll down to Your tax returns & documents.
4. Select 2019, and then select Add a State (you're not actually adding a state, this just gets you into the right area).
5. Select File in the left menu (expand your browser window if you don't see this, or select the menu icon in the top left corner).
6. On the Just one more step screen, follow steps 1 and 2 if you haven't already.
7. Select the Start button to the right of Step 3.
8. On the Let's get ready to e-file screen, select I want to e-file.
9. Follow the instructions to e-file your return.