To file a return for a prior tax year
If you need to prepare a return for 2016, 2017, or 2018 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
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/state received the return.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
I just used TurboTax 2018 Deluxe edition (online download to windows 10) to file my 2018 taxes, and it calculated that I did not owe any penalties or late fees! Cool!!!
Unfortunately, I am thinking I am going to still owe them no matter what TT 2018 software says....
Did you owe tax due on the 2018 return? TurboTax will not calculate the late filing penalties and interest. You can expect a bill from the IRS later -- the IRS calculates it based on how much you owed and when they receive your payment.
I see you recently cheered the original solution in this thread about preparing a 2017 return. This is a thread that is a couple of years old that transferred into this new Community forum last June.
While it's not too late to file a 2017 return prepared with TurboTax, you cannot prepare the 2017 return in Online TurboTax, (web version) which is only for 2019 returns at this point in time. You would have to use 2017 desktop software as explained in detail elsewhere in this thread.
You may have already known that, but I wanted to make sure you do NOT try to prepare 2017 return using the 2019 Online TurboTax interface (i.e., the web version). We have sometimes seen a user try to prepare the wrong tax year online by mistake.