I never filed my 2014 2016 2018 but I have the w2's can I still go back and do them and can I do them on turbo tax

You can use TT for returns from 2016 to 2019.  In order to get a refund, 2016 has to be filed by April 15, 2020 or it will be too late.

Software for earlier years than 2016 is no longer available.  Refunds for earlier years than 2016 have been forfeited now.  But if you owe tax the IRS still wants to be paid.  A 2014 or 2015 return can be prepared on the paper form and must be mailed in.

ONLY a 2019 return can be prepared using the online software program.

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

2015

Form 1040  https://www.irs.gov/pub/irs-prior/f1040--2015.pdf

Form1040 Instructions  https://www.irs.gov/pub/irs-prior/i1040gi--2015.pdf

Form1040A  https://www.irs.gov/pub/irs-prior/f1040a--2015.pdf

Form 1040A Instructions  https://www.irs.gov/pub/irs-prior/i1040a--2015.pdf

Form 1040EZ   https://www.irs.gov/pub/irs-prior/f1040ez--2015.pdf

Form 1040EZ Instructions  https://www.irs.gov/pub/irs-prior/i1040ez--2015.pdf

2014

Form 1040 https://www.irs.gov/pub/irs-prior/f1040--2014.pdf

Form 1040Instructions  https://www.irs.gov/pub/irs-prior/i1040gi--2014.pdf

Form1040A   https://www.irs.gov/pub/irs-prior/f1040a--2014.pdf

Form 1040A https://www.irs.gov/pub/irs-prior/i1040a--2014.pdf

Form1040EZhttps://www.irs.gov/pub/irs-prior/f1040ez--2014.pdf

Form1040EZ Instructions https://www.irs.gov/pub/irs-prior/i1040ez--2014.pdf

NOTE:   Each year must be prepared separately and must be mailed in separately.  Do not try to combine tax years in any way.

Yes, you should go back and file your tax returns for previous years, if for no other reason than to start the statute of limitations period. 

If you are due a refund for 2014, you will not receive it because too much time has passed.  If you file your 2016 return by April 15, 2020, you should still get your refund if you are due one.

The TurboTax online product is only valid for your 2019 return but you will be able to purchase and download the software for your 2016 and 2018 returns and install it on your computer.  We no longer have the software for 2014 .  To download TurboTax for previous years, please follow these steps:

1. Go to the TurboTax website.
2. Click Products & Pricing.
3. Select Previous years' products from the menu.
4. On the next screen you will see a list and description of the 2018 products.
5. Click Buy Now under the product you want to purchase and follow the instructions on the screen.

If your return is very simple, you can access the forms on the IRS website by clicking this link:  Search For Prior Year Forms  You can download the forms and fill them out by hand.