Paper employer withholding and school district withholding forms are no longer available. Electronic filing has been mandatory since 2015.All employer withholding returns and payments are required to be made electronically. Complete Form W-4 so that your employer can withhold the correct federal income tax from your pay. Give Form W-4 to your employer. To file online, log in to the Ohio Business Gateway or Employer Resource Information Center (ERIC) to file and pay any taxes online. As of 2015, Ohio requires employers to submit efilings. 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. Workplace tax refers to a tax paid to a municipality in which an employee works, regardless of where that employee lives.