Key takeaways IRS Form SS-4 is used to obtain an Employer Identification Number (EIN) for your business or other entity such as a trust or estate. The SS-4 form requires detailed information about ...

IRS Form SS-4, Application for Employer Identification Number, is a form businesses use to apply for an employer identification number (EIN).

You can either apply by fax, mail or online. If you apply by fax or mail, you must fill out and submit the IRS Form SS-4. If you need your EIN number fast, you can apply online.