Can I submit online after I already asked to print and mail my tax forms?

[KrisD]

Yes. 

If you already mailed your return, don't e-file. This can cause problems with the government, including refund delays.

1. In TurboTax Online, sign into your account.
2. Scroll to "your tax returns & document". select "Add a State" (don't worry, a state will not be added and you wont be charged)
3. Select File in the left menu.
4. On the Just one more step screen, follow steps 1 and 2 if you haven't already.
5. Select the Start button to the right of Step 3.
6. On the Let's get ready to e-file screen, select I want to e-file.
7. Follow the instructions to e-file your return.