You can apply for an Employer Identification Number (EIN) with the Internal Revenue Service (IRS) in the United States by following these steps:

Determine if you are eligible: EINs are issued to entities that have a valid tax filing requirement, such as businesses, non-profit organizations, estates, and trusts. Make sure you meet the eligibility criteria before applying.

Choose a method of application: There are several ways to apply for an EIN. You can apply online, by mail, by fax, or by phone. The online application is the most convenient and fastest method, and it is available for most applicants.

Complete the application form: The application form for an EIN is called Form SS-4, which is available on the IRS website. If you are applying online, you will need to complete the online version of Form SS-4. If you are applying by mail, fax, or phone, you will need to download and print Form SS-4, then complete it manually.

Provide accurate information: Make sure to provide accurate and complete information on your EIN application, including your legal name, Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN), business name, business address, and other required details. Incorrect or incomplete information may cause delays in processing your application.

Submit your application: If you are applying online, you can submit your completed online Form SS-4 electronically on the IRS website. If you are applying by mail, fax, or phone, you will need to follow the instructions on Form SS-4 to submit your application to the appropriate IRS office.

Wait for your EIN: Once your application is submitted, the IRS will process it and issue you an EIN. If you applied online, you will receive your EIN immediately after submitting your application. If you applied by mail, fax, or phone, it may take several weeks to receive your EIN.

Keep your EIN safe: Once you receive your EIN, make sure to keep it in a safe place as you will need it for various tax-related purposes, such as filing tax returns, opening a bank account for your business, and applying for business licenses.

Note: There is no fee to apply for an EIN. Be cautious of any third-party websites that charge a fee for EIN application services, as you can easily apply for an EIN directly with the IRS for free.