See this TurboTax support FAQ for completing a prior year tax return started with the online editions - https://ttlc.intuit.com/questions/2559403-how-do-i-finish-a-prior-year-return-that-i-started-in-turb...

If you never started a 2016 tax return then go to this website to purchase and download one of the 2016 desktop editions - https://turbotax.intuit.com/personal-taxes/past-years-products/

A 2016 tax return can only be printed and mailed, it cannot be e-filed.