A Tax ID or ITIN NUMBER is an identification number used by foreigners who are physical taxpayers but cannot obtain a Social Security Number (SSN) to declare their taxes and obtain a refund of the income withheld by the IRS. Those who are not eligible for a Social Security Number (SSN) can obtain an ITIN, regardless of their immigration status or country of origin. People often need a Tax ID because they have been advised by a bank that they cannot open a bank account without that number even if the account is opened by a non-profit organization.
The Employer Identification Number (EIN) is a unique number for commercial entities operating in the United States. It is a nine-digit number assigned by the Internal Revenue Service (IRS), and has a function similar to the CNPJ, used in Brazil.
The EIN is also known as Federal Employer Identification Number (FEIN) or Federal Tax Identification Number.