What happens if I did not add form 1095-c to my taxes? How do I add it after ive already efiled and the IRS accepted them?

Nothing will happen---you are not supposed to enter a 1095C to your tax return.   You only enter a 1095A if you had marketplace heath insurance from healthcare.gov.

You do not have to enter it. As per xmasbaby0, you are not required to file Form 1095-C with your taxes. Form 1095-C is a statement of health coverage offered to eligible employees. Sending out Forms 1095-C has been required since the 2015 tax year but you do not have to report it on your taxes. Keep it with your tax records.

Click here for additional information on Form 1095-C.

Click here for additional information on Forms 1095-C and 1095-B.