TurboTax 2016 online is now closed, so there is no longer a Free Edition available through TurboTax.
To use TurboTax for 2016, you'll have to purchase the software for what is now a "prior year". You'll also need to print and mail your tax return.
Free File via the IRS is also closed for tax year 2016.
Here's the link to the TurboTax webpage to purchase for 2016.