I didn't file last years so can i file them now all at once because it has all three totaled together am i right or wrong?

[xmasbaby0 · Accepted solution]

NO!  You cannot combine income from several years on the same tax return.  Each tax year has to be filed separately using the forms and software that comply with the tax laws in effect when the income was received.

The current online software is ONLY for a 2018 return reporting income from 2018.

To file a return for a prior tax year

 If you need to prepare a return for 2015, 2016, or 2017 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.

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.