Mar 13, 2019 Individuals need their W-2s to file an accurate tax return, as the form shows your income and taxes withheld for the year. So what do you do if you If you are unable to attach W-2s and/or 1099s to your e-filed return, submit. show Colorado income tax withholding must be stapled to the front of the form where indicated. If you are unable to attach W-2s and/or 1099s to your e-filed return, submit through Revenue Online. Show W-2-Didn't Receive From Employer.