All businesses are required to pay federal, state, and in some cases, local taxes. Most businesses will need to register with the IRS and state and local revenue agencies, and receive a tax ID number or permit.
The following resources will help determine your tax registration requirements.
An EIN is also known as a federal tax identification number, and is used to identify a business entity. Employers with employees, business partnerships, and corporations and other types of organizations, must obtain an EIN from the U.S. Internal Revenue Service. The EIN is also known as an Employer Tax ID and Form SS-4:
U.S. Internal Revenue Service
Businesses that operate within the state are required to register for one or more tax-specific identification numbers, licenses or permits, including income tax withholding, sales and use tax (seller's permit), and unemployment insurance tax. The State Tax Guide provides links to information about business registration requirements and your tax obligations in your state.