The TIN Type you will select for your organization will be based on how you plan to do business with the State of Colorado.

If you will be doing business using a Federal Tax ID number for your organization, you will want to select I will use my entity's Employer Identification Number (EIN).

If you will be doing business as an Individual, you will want to select I will use a Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or Adoptive Identification Number (ATIN). If you select this option as your TIN type, you will need to be sure to select whether you have an SSN, ITIN, or ATIN that you will be providing.

The best practice is to refer to your most recent W9 for this information.