If you were getting a refund for your 2016 tax return there is not a penalty for filing late. If you owe tax for that year, then your penalties and interest have been accruing. It is not too late to file your 2016 tax return.
Online preparation and e-filing for 2016 is permanently closed.
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)
https://turbotax.intuit.com/personal-taxes/past-years-products/
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.