Registrations & IDs CIN, LLPIN & DIN Identifiers issued by the Ministry of Corporate Affairs. Company Law & ROC Company Types & CIN Private, public, OPC, Section 8 and LLP, and how to read a CIN. Registrations & IDs GSTIN How a GSTIN is built and checked. Registrations & IDs PAN & TAN PAN structure, holder types, PAN-Aadhaar link, and TAN for TDS. Registrations & IDs Udyam Number The Udyam Registration Number format. MSME & Udyam Udyam Registration Free online registration, the Udyam number format, updates and Udyam Assist. E-Invoice QR code and signed QR on e-invoices What is inside the signed QR, how to verify it, and the separate B2C dynamic QR.