What document is required to apply for an EIN as an employer?

To apply for an Employer Identification Number (EIN), the required document is Form SS-4. This form is specifically designed to collect the necessary information from businesses and organizations that are applying for an EIN. It allows the Internal Revenue Service (IRS) to assign a unique identifier that will be used for various tax-related purposes and helps the agency in managing tax compliance for employers.

The significance of using Form SS-4 lies in its comprehensive nature, which collects information such as the legal structure of the business, the reason for applying for the EIN, and the details of the responsible party. This facilitates the IRS's understanding of the entity's operations and tax obligations.

Other forms, such as Form W-2, Form IT-4, and Form 1040, serve different purposes in the tax system and are not applicable for obtaining an EIN. Form W-2 is used to report employee wages and taxes withheld, Form IT-4 is a state withholding allowance certificate, and Form 1040 is the individual income tax return form. These documents do not initiate the process of getting an EIN, which is why Form SS-4 is the appropriate choice for this requirement.