What this notice is about We assigned you a Personal Identification Number (PIN) to associate your existing Centralized Authorization File (CAF) number through Tax Pro Account for identity assurance. You don't need to call or respond to this notice. What you need to do with the PIN Use the PIN number to verify your identity and complete your request: Sign in to Tax Pro Account. Associate your CAF number to your personal information by entering your PIN. You may want to Keep your PIN in a safe place for your records. Call the IRS number at the top of your notice if you didn't request a PIN or if you have questions. Important things to remember about your PIN It can only be used to verify ownership of your CAF number in Tax Pro Account and will expire in 30 days. It is unique to your CAF number. It is for your use only. Keep it secure and don't share it with anyone. Helpful information Find how to submit Form 2848, Power of Attorney and Declaration of Representative or Form 8821, Tax Information Authorization to a taxpayer's online account with Tax Pro Account. Read more about CAF Authorization Rules. Reference Tools Publication 1, Your Rights as a Taxpayer Publication 947, Practice Before the IRS and Power of Attorney Third Party Authorization Purpose Full list of tax forms and instructions Need help? You can authorize someone to represent you before the IRS or inspect and/or receive confidential tax information. You may be eligible for free help from the Taxpayer Advocate Service (TAS). See if you qualify for help from a Low Income Taxpayer Clinic. You can request a copy of your notice or letter in Braille or large print. If you can’t find what you need online, call the telephone number on your notice or letter.