When you sign onto to your online account using the exact same user ID you used to create, complete and file the 2016 tax return you will land on the Welcome Home screen. Click on the blue link - Download/print return.
Or when you land on the Welcome Home screen click on My TurboTax at the top left of the program screen. This will take you to the 2016 Timeline. Under the section Some things you can do: Click on either Download/print return (PDF) or Download all forms and worksheets.