Each of those will be a separate return. Do not try to combine income from different tax years in any way at all--do not even try to mail them in the same envelope.
The ONLY year that you can prepare using the current online program is 2019. Any other years must be prepared using the purchased desktop software for each individual year. All desktop software has all of the forms and schedules needed so try starting with Deluxe and upgrade only if you need to.
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)
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/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.
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.
https://ttlc.intuit.com/questions/1900990-how-do-i-file-a-prior-year-tax-return
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
