GST registration requirements: timely application, PAN/TAN eligibility, single registration with separate verticals and enforcement powers. The provision prescribes GST registration procedure: liable persons must apply within prescribed timeframes while casual and non-resident taxable persons require earlier notice; single registration is standard with separate registrations possible for distinct business verticals. Multiple registrations or establishments are treated as distinct persons. Applicants generally must have a Permanent Account Number, with TAN acceptable for tax deductors and alternative documents for non-residents. The proper officer may register defaults; specified international agencies and notified persons may receive a Unique Identity Number. Grant, rejection, certificate issuance and deemed registration follow prescribed verification and timelines.