Can I save and return to doing my taxes on TurboTax?

[mesquitebean]

Yes, you can come and go.   Online TurboTax saves your work each time you change screens, even if you were to accidentally close the browser or get disconnected.

The correct way to exit is to go to the left menu column, and scroll way down to the bottom of that menu and choose Sign Out.   When you return for another session, once you log into the Tax Home, there should be a "Take me to my return" button.