Certificate of Residence. How to Complete the Form.Step 1: Log in to the application status portal to reply to your offer of admission from Allegheny to tell us your plan. Step 2: Submit your enrollment deposit. If you do not have a real property tax bill, call the county assessment office ). 2. Employee works in Philadelphia for a large employer which has its payroll department in Mt. Lebanon, Allegheny County, PA. Employer has elected to file combined. This form allows the employee to verify that the employer is withholding the correct tax rates for the correct municipalities. We maintain yearly records on over 550 thousand parcels.