The Taxpayer Identification Number (TIN) is an umbrella term and it comprises several different types of tax IDs. The three most important TIN's are Social Security Number (SSN), Employer Identification Number (EIN), and Individual Taxpayer Identification Number (ITIN).
A taxpayer identification number (TIN) is required on all returns, statements, and other tax-related documents and you must provide it upon request to any other person who needs it to comply with the tax law. For most individuals, their TIN is a Social Security number (SSN).
The unique TIN consists of 9-12 digit numeric code in contrast to the alphanumeric TAN, thus easier to encode. To illustrate, consider this TIN: 000 – 123 – 456 – 001 i. The first digit which is “0” signifies that the TIN belongs to a corporation; ii.