You mean your W-2 is showing "0" in box 2 for federal tax withheld? Where does it say zero? What box has "4"?
If your manager does not know what is supposed to be on your W-2 then is there a payroll department you can ask? We cannot help you by telling you to change it. Whatever the employer put on the W-2 is what they reported to the IRS. You need to sort this out with your employer.
Or are you really asking about your W-4 that shows how many allowances you are claiming -- which affects how much tax they withhold from your paycheck? Please explain more.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**