The CAF is the number that the Internal Revenue Service assigns to you if you are authorized to represent a taxpayer before the IRS.
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
The number is XXXXX to a tax practitioner. This number represents a file that contains information regarding the type of authorization that taxpayers have given representatives for the various work within their accounts.
I hope this helps,