What this notice is about We received your Form 2848, Power of Attorney and Declaration of Representative, Form 8821, Tax Information Authorization, or Form 706, U.S. Estate Tax Return, 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. Frequently asked questions What is a CAF number? 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. If we assigned you more than one CAF number and you didn’t specifically request more than one, please fax a copy of each CP547 notice you received to the fax number in the notice using either a fax machine or an online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies. What should I do if I don’t remember my CAF number? If you’re a tax professional and can’t remember your CAF number, you can call the Practitioner Priority Services (PPS) at 866-860-4259. Once authentication is verified for the client and representative, your CAF number can be provided over the phone. If the Customer Service Representative (CSR) is unable to authenticate you as the owner of the CAF number, a 1727C Letter will be issued to the CAF address of record for the representative. Reference tools Publication 1, Your Rights as a Taxpayer Full list of tax forms and instructions Cần trợ giúp? Bạn có thể ủy quyền cho ai đó (tiếng Anh) thay mặt bạn liên lạc với IRS. Xem liệu bạn có đủ điều kiện để nhận được sự trợ giúp từ Trung tâm cho Người đóng thuế có thu nhập thấp. Nếu bạn không thể tìm thấy những gì bạn cần trực tuyến, hãy gọi cho IRS theo số ở đầu thông báo hoặc thư gửi cho bạn. Nếu bạn không nhận được thư hoặc thông báo, sử dụng hỗ trợ qua điện thoại. Nếu bạn không thể tự mình giải quyết hình phạt, liên hệ Dịch vụ Biện hộ Người đóng thuế, một tổ chức độc lập trong IRS.