An Employer Identification Number (EIN) is also known as a Federal Tax Identification Number, and is used to identify a business entity.
(SOURCE – IRS Website)
First of all, your EIN is like the Social Security Number for your business. You will use it on applications, on tax forms, to open your bank account. It is how the IRS knows your business.
If you take the time to create an entity for your business, you should make sure and secure an FEIN.
Typically, a bank will require an FEIN and your Certificate of Formation to open a bank account for your new legal entity.