See this TurboTax support FAQ for IRS forms availability - https://ttlc.intuit.com/questions/1908854-irs-forms-availability-table-for-turbotax-individual-perso...
Click on Review at the top of the program screen. In the Review section is a screen that shows the forms and schedules included in your tax return that have not been finalized and the date they will be available.
Once the forms and schedules for your tax return have been finalized you will need to return to your 2016 online account to complete and e-file the tax return. Click on File at the top of the program screen. Follow through the File interview until you are in the section for e-filing the return by clicking on the Transmit Return button.