Every organization in US need to have Employer Identification Number (EIN), even if it has no employees in the organization. EIN is a nine-digit unique number which identify an organization to the IRS. In order to apply for an EIN one need to obtain the application Form SS-4 from IRS website. One can apply for an EIN from IRS website – online, by mail or by fax. One may also apply for an EIN by phone, if their organization reside outside of US or US territory.