Officer's Compensation Doesn't match w2 filed

My officer's compensation does not match the w2 that was filed.  I know the difference is in health insurance premiums considered as compensation.  I think the instructions said that I could attach a page to explain the difference, but now I can't find that, or figure out how to attach a page to e-file.  Is there a way to attach a page and e-file, or will have to mail the return?  Or is there another solution?  Thanks.