TurboTax does not support tax year 2016
To complete and file a 2017 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2017 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/
A 2017 tax return can only be printed and mailed, it cannot be e-filed.
Sorry---that is not going to work out. You cannot use online to prepare a 2016 or 2017 return, nor can you use refund processing for those returns. You have forfeited your tax refunds for those tax years--it is too late. Software is not available for 2016 at all. You can still get the CD/download for 2017 but it must be purchased and installed to a full PC or Mac. Unless you had an extension for 2017 (which you had to request by April of 2018) you cannot get a refund for 2017.
If you owe tax for those years it still has to be paid with interest and late filing penalties.
Online preparation and e-filing for 2017, 2018 and 2019 is permanently closed. The online software can only be used for a 2020 return--no other year.
To file a return for a prior tax year
If you need to prepare a return for 2017, 2018, or 2019 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.
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.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.
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.
If you are getting a refund, there is not a penalty for filing past the deadline. If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.
Refunds for tax years 2016 or earlier have been forfeited and will not be paid to you even if shown on the tax return form. But if you owe tax due, you will still have to pay, and you will be billed later for the interest and penalties owed.
If you want to use paper forms and prepare them by hand to mail in:
Form 1040 Instructions https://www.irs.gov/pub/irs-prior/i1040gi--2016.pdf
Form 1040A https://www.irs.gov/pub/irs-pdf/f1040a.pdf
Form 1040AInstructions https://www.irs.gov/pub/irs-prior/i1040a--2016.pdf
Form 1040EZ Instructions https://www.irs.gov/pub/irs-pdf/i1040ez.pdf