TIN stands for Tax Identification Number. That’s either your Social Security Number (SSN) or Employer Identification Number (EIN), depending on how you filled out your W-9 form in your Raptive dashboard.
You can check to see which you used by logging in to your dashboard, and navigating to Payments > Payment Info.
Click through to Page 3: Tax Forms.
Click where it says "To view the information you submitted, click here."
Under "W9 Form Details", it will list which tax identification number you entered on the W-9 form.