A CAF number is a unique nine-digit identification number and is assigned the first time you file a third party authorization with IRS. A letter is sent to you informing you of your assigned CAF number. Use your assigned CAF number on all future authorizations.
CAF numbers are different from the third party's TIN (Taxpayer Identification Number), EIN (Employer Identification Number) or PTIN (Preparer Identification Number). CAF numbers may be assigned to an individual or a business entity.
If you are a tax professional and cannot remember your CAF number, you may call the Practitioner Priority Service, otherwise known as PPS. PPS may be reached at 866-860-4259. A PPS assistor will initiate the process to help you retrieve your CAF number once you provide your authenticating information.