How do I get my taxpayer ID number??

Your taxpayer ID number is your Social Security number or the ITIN that was issued to you by the IRS.

Your Tax ID is your Social Security number.   Or if you are self-employed and do not want to give your SSN to clients, you can get a Tax ID (EIN) from the IRS to use.

https://www.irs.gov/businesses/small-businesses-self-employed/how-to-apply-for-an-ein