The IRS W-9 form provides information for people who are filing on behalf of eligible institutions to get their correct Taxpayer Identification Numbers (Tins) to be included in the filing. When filing Form 1098-T, provide the correct TIN, also known as a Taxpayer Identification Number, (TIN), in your signature box. 2 Contact Information for the individual or organization. The person responsible for sending you Form W-9; Address: San Diego County Human Services Agency P.O. Box 639082 San Diego, CA 92 Phone Number: Mail Address: Department of Human Services 5001 North B Street Room 11 San Diego, CA 92 This information is for informational purposes only. We make no warranties or representations, and hereby disclaim any and all claims or warranties, expressed or implied, including, but not limited to, implied warranties of merchantability or fitness for a particular purpose, that the information or product provided is error or that the information or product shall be free of defrauding, deceptive, or misleading claims. Information provided through this Website is not intended to replace or limit, for any specific information, an agent's best effort to advise. Disclaimer: The information contained in this website is provided as general information only, and not as advice or a substitute for the careful review of particular tax issues.