I got a letter from I RS day an I didn't file my w2 for insurance an an 8962 form how can I do this if already filed

[DoninGA]

What tax year is the IRS letter referring to?

[LeonardS]

If you have filed your tax return and then discover that you have an additional W-2 to file you will have to wait until the IRS either accepts or rejects your tax return.

If the return is rejected you will correct the error that caused the rejection, add the W-2 and refile your return.

If the return was accepted by the IRS then you will have to file an amended tax return using Form 1040X to add the W-2 to your tax return. 

This link to the TurboTax Help page  How to amend (change or correct) a return you already filed provides information on how to amend your tax return.