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.
As mandated by the Internal Revenue Service, every individual who is required for U.S. tax purposes to have a U.S. Taxpayer Identification Number, but who is ineligible for a Social Security number, must attach Form W-7, Application for IRS Individual Taxpayer Identification Number, to the income tax return for which the Individual Taxpayer Identification Number is needed.