You can but only if you have NOT mailed your return. If you already mailed it and then you e-file, your return will be delayed, probably for a really long time.
Sign into your return and click on Take me to my return. On the Tax Home page, scroll down until you see ''Add a State''. This will unlock your return. Then you go to FILE, change your filing method to E-file and proceed.
How do I change from File by Mail to E-file in TurboTax Online? see image.
