As of June 2015, those eligible for an Employer Identification Number can apply for one online, states the Internal Revenue Service; the Social Security Administration does not allow online applications for Social Security numbers. An Employer Identification Number is a federal ID for businesses while the Social Security number is used for individuals.
Employers are allowed to apply online for an Employer identification Number if their principal business is located on the United States or one of the country's territories, notes the IRS. The number will be available immediately after the application is completed and approved.
Those needing a Social Security number must apply through the mail or in person at a Social Security office. They must have the required documents ready before applying. This process is free.