Information For...

For you and your family
Standard mileage and other information

Forms and Instructions

Individual Tax Return
Instructions for Form 1040
Request for Taxpayer Identification Number (TIN) and Certification
Request for Transcript of Tax Return


Employee's Withholding Allowance Certificate
Employer's Quarterly Federal Tax Return
Employers engaged in a trade or business who pay compensation
Installment Agreement Request

Popular For Tax Pros

Amend/Fix Return
Apply for Power of Attorney
Apply for an ITIN
Rules Governing Practice before IRS

Understanding Your CP547 Notice

We received your Form 2848, 8821, or 706, and we assigned you a Centralized Authorization File (CAF) number.

What you need to do

  • Keep this notice so you know what your CAF number is for all future third party authorization requests and telephone contacts with the IRS on behalf of the taxpayer.

You may want to

  • Keep your CAF number in a safe place for future reference.
  • Notify the IRS if this was assigned without your knowledge.


Answers to Common Questions

Q. What is a CAF number?

A. A CAF number is a unique nine-digit identification number that we assign to you the first time you file a third party authorization with the IRS. We send a CP547 notice to you informing you of your assigned number. Use your assigned number on all future authorizations.

Q. What should I do if I don’t remember my CAF number?

A. If you’re a tax professional and can’t remember your CAF number, you can call the Practitioner Priority Services (PPS) at 1-866-860-4259. Once you provide your authenticating information, they can verbally give your CAF to you over the phone. If PPS is unable to authenticate you as the owner of the CAF number, they will mail the number to the CAF address of record.


Printable samples of this notice (PDF)

How to get help