I completed tax return using Turbotax 18. I have not efiled yet. But Near the end, I selected to print my returnt Now, I need to go back in Turbotax, to complete efiling.

Close out of TT and relaunch (restart) the application. Once you're back in, select your filing by clicking "Continue". In the second row of menus, click on "File". It will prompt you to continue.