The TurboTax online editions are only for tax year 2017. If you need to complete and file a 2016 tax return then clear the 2017 return. Click on Tax Tools on the left side of the screen. Click on Clear & Start Over. Exit the program.
To complete a 2016 tax return using TurboTax you will need to purchase and download one of the 2016 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/
A 2016 tax return can only be printed and mailed, it cannot be e-filed.