Article 15 of the GCC Common Excise Tax Agreement establishes the core compliance requirement for filing tax returns. It mandates that any person who is required to register for excise tax must file a tax return. The Agreement provides each Member State with the authority to determine its own specific tax period or periods. However, this authority is subject to a key constraint: the designated period cannot be less than one month or more than one year. The Article also grants individual Member States the discretion to except importers from the obligation to file tax returns.