Lets say I have a W2 form from 2014 that I forgot to file for some years. Is it possible for me to file a 2014 W2 form in the present year of 2020?

Only 2019 income can be filed on a 2019 tax return. You cannot use your 2014 W-2 on a 2019 tax return. 

That W-2 could only be used on a 2014 tax return, but it is now too late to file a 2014 tax return and receive a refund.  If you would have received a refund, you forfeited it a couple of years ago.  If you owe for 2014, the IRS still wants to be paid.  If you want to file a 2014 return then you can get the paper forms from the IRS and prepare a 2014 return to mail in.

https://www.irs.gov/forms-pubs/prior-year

check out TaxACT which still offers the 2014 program.

You need the 2014 forms to file a 2014 tax return.

If you are looking for a refund, it is too late, your refund is forfeited.