Registration requirement: GST enrolment within prescribed time creates single registration with exceptions for verticals and non residents. Every person liable must apply for registration within thirty days, with casual and non resident taxable persons applying before business commencement; supplies from territorial waters require registration in the State nearest the baseline. A person is entitled to a single registration, subject to separate registrations for distinct business verticals. Registration eligibility requires a Permanent Account Number, while deductors may use a Tax Deduction and Collection Account Number and non residents may submit prescribed alternative documents. The proper officer may register non applying liable persons. A Unique Identity Number may be granted to specified international agencies and notified persons, and registration is issued, verified, and deemed granted if no deficiency is communicated within the prescribed period.