You cannot use TurboTax Online to file for past years. TurboTax Online is only for the current tax year, which is now 2017. To file for previous years you have to use the CD or download TurboTax software for the year or years that you need. You can purchase downloads at the following link. You have to purchase a separate program for each year that you need to file. TurboTax is no longer available for years earlier than 2014.
http://turbotax.intuit.com/personal-taxes/past-years-products.jsp
You might get a better price from a reputable online seller that still has TurboTax in stock for the years that you need.
TurboTax does not allow returns for past years to be e-filed. You will have to print your past-year tax returns, sign them, and file them by mail.
