As mandated by the Internal Revenue Service, every employer that withholds taxes from employees' pay must establish a business account with the Internal Revenue Service by filing Form SS-4, Application for Employer Identification Number.
As mandated by the Internal Revenue Service, pension or annuity recipients file Form W-4P, Withholding Certificate for Periodic Pension or Annuity Payments, with pension payers to indicate the desired amount to be withheld from the pension or annuity distribution.