Registration requirement: liable persons must obtain prescribed registration; PAN and Unique Identity provisions govern eligibility and exceptions. Persons liable to GST registration must apply within prescribed timelines; casual and non resident taxable persons have advance application requirements. Single registration is the norm, with separate registrations permitted for distinct business verticals. Voluntary registration makes a person subject to all registered-person provisions. Each registration or establishment across States is treated as a distinct person. PAN is required for registration eligibility, with alternatives for certain deductors and non residents. Proper officers may register defaulters and special international or notified entities may receive Unique Identity Numbers; grant, rejection, and issuance follow prescribed verification and timeframes.