Registration under GST law requires state wise registration, PAN/TAN eligibility, and Unique Identity Numbers for notified entities. Registration requires persons liable under the schedule to apply in each State within the prescribed period; casual and non resident taxable persons must apply earlier. Separate registration is permitted for multiple business verticals; voluntary registration is available. PAN is required for eligibility, with TAN acceptable for specified deductors and prescribed alternatives for non residents. The proper officer may register non compliant persons; specialized agencies and notified persons obtain a Unique Identity Number for notified purposes. Registrations and Unique Identity Numbers are subject to prescribed verification, deemed grant where no deficiency is communicated, and mutual recognition between central and State registrations, while governments may notify exemptions.