What is the Purpose of IRS Form 941?
According to the IRS, "Federal law requires you, as an employer, to withhold taxes from your employees' paychecks." Thus, each time an employers pays wages, that employers must withhold certain amounts for federal income tax, social security tax, and Medicare tax, (and if required by that State, amounts for State income taxes).
Under the withholding system established by the IRS, these payroll taxes (that is Medicare and Social Security taxes) withheld from employees are credited to the those employees in payment of their tax liabilities.
Under the current Federal law, Employers are required to pay any liability for the employer's portion of social security and Medicare taxes. This portion of social security and Medicare taxes is not withheld from employees. Thus, the employers generally are required to match the employees share of both Medicare and Social Security Taxes.