Online preparation and e-filing for a 2016 return is permanently closed. A 2016 return can only be printed, signed and mailed. You could not have e-filed anything for 2017 because the IRS is not yet accepting tax returns for 2017.
To file a return for a prior tax year
Only a 2017 return can be prepared online and e-filed.
If you need to prepare a return for 2014, 2015, or 2016 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: )
You can download the Forms and Instructions from the IRS web site:
Remember to prepare your state return as well—if you live in a state that has a state income tax.