Submit form IT 4 to your employer on or before the start date of employment so your employer will withhold and remit Ohio income tax from your compensation. Complete el Formulario W-4 para que su empleador pueda retener la cantidad correcta del impuesto federal sobre los ingresos de su paga.Paper employer withholding and school district withholding forms are no longer available. Electronic filing has been mandatory since 2015. Information about Form W4, Employee's Withholding Certificate, including recent updates, related forms and instructions on how to file. You will need to fill out a W-4 form when you start. A W4 form, or "Employee's Withholding Certificate," is an IRS tax document that employees fill out and submit to their employers. Learn how to fill out a W4 form with this updated indepth guide for 2025. Use Form I9 to verify the identity and employment authorization of individuals hired for employment in the United States. Employee's Withholding Exemption Certificate.