This document is the official User Manual for the UDIN Portal, provided by the Institute of Chartered Accountants of India (ICAI). It offers a comprehensive guide to using the UDIN portal, covering everything from initial login and dashboard navigation to generating UDINs for various document types like certificates, tax audits, and assurance functions. The manual also details how to manage UDINs, handle grievances, and verify UDINs, making it an essential resource for all ICAI members.