What is a CAF number?
Accountants, Attorneys, enrolled agents or other representatives from whom a taxpayer has requested assistance on tax problems submit inquiries to IRS. The third party expects a reply to the inquiries so that problems can be explained to the taxpayer. To authorize this third party reply, the representative may submit a Form 2848, Power of Attorney and Declaration of Representative (PDF), or Form 8821, Tax Information Authorization (PDF).
A CAF number is assigned to a tax practitioner when a Form 2848 or Form 8821 is filed. This number represents a file that contains information regarding the type of authorization that taxpayers have given representatives for the various modules within their accounts. If you are a tax practitioner who has previously been assigned a CAF number but cannot locate the number, call the Practitioner Priority Service, who will mail your CAF number to you.
Specific use authorizations generally are not recorded on the CAF database. These authorizations must be provided by the representative with each contact with the IRS.