Employers and other third parties (e.g., banks, military recruiters) often need to know the Social Security number assigned to an individual. Form SSA-7028 (Notification of SSN to Third Party) is used for this purpose. The form is completed by the local office where you have applied for your Social Security number and is sent to the third party. Social Security does not have the form online as it is only used by Social Security offices and is not intended for public use.