Article 50 mandates VAT registration for residents in a Member State if the value of their annual supplies exceeds the Mandatory Registration Threshold of SAR 375,000. This threshold may be amended by the Ministerial Committee after three years. Non-residents must register regardless of turnover if they are liable to pay tax in the State; they may appoint a tax representative, subject to Article 43(2). Additionally, a Taxable Person making exclusively zero-rated supplies may apply for exemption from mandatory registration, subject to local Member State conditions. This ensures proper compliance while offering flexibility for specific business structures.