To be recognized as exempt under section 501(a), most organizations must file an application for recognition of exemption with the IRS. Most organizations applying for exemption under section 501(a) (other than section 501(c)(3)) use Form 1024. Form 1024 has instructions and checklists to help you provide the information required to process your application. The IRS will not process an incomplete application.
The IRS sometimes recognizes a group of organizations as tax-exempt if they are affiliated with a central organization. This avoids the need for each organization to apply for exemption individually. A group exemption letter has the same effect as an individual letter except that it applies to more than one organization. For more information about group exemption requirements and procedures, see Publication 4573, Group Exemptions.