To file a return for a prior tax year
Only a 2016 return can be prepared online and e-filed.
If you need to prepare a return for 2013, 2014 or 2015 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
(if you want to prepare on paper for free)
Remember to prepare your state return as well—if you live in a state that has a state income tax.