It cannot be done online. TurboTax Online is only for the current tax year.
And the 2016 return would then need to be prepared, printed and mailed. You cannot e-file a prior year return.
The other option would be to download the Forms and Instructions, free, from the IRS website at this link
https://www.irs.gov/forms-pubs complete them by hand and mail to them.
How do I file a prior year tax return?
