Taxpayer Identification Numbers (TIN) are used to associate and verify amounts you report to the IRS with corresponding amounts on tax returns. Therefore, it is important that you furnish correct names, social security numbers (SSNs), individual taxpayer identification numbers (ITINs), employer identification numbers (EINs), or adoption taxpayer identification numbers (ATINs) for recipients on the forms sent to the IRS.
Request a TIN from the Donor. If the donor is a U.S. person (including a U.S. resident alien), the IRS suggests that you request the donor complete Form W-9, Request for Taxpayer Identification Number and Certification. See the Instructions for the Requester of Form W-9 for more information on how to request a TIN.
If the donor does not provide a TIN, you must check box 7 of Form 1098-C because the acknowledgment will not meet the requirements of section 170(f)(12) and the donor will not be allowed to claim a deduction of more than $500 for the qualified vehicle.
If you check box 7, do not file Copy A with the IRS and do not furnish Copy B to the donor.