Advance ruling under GST clarifies classification, notification applicability, time/value of supply, input credit and registration obligations. Applications for an advance ruling must be made in the prescribed form and manner with the prescribed fee, stating the specific question. Permissible questions are limited to classification of goods or services; applicability of notifications; determination of time and value of supply; admissibility of input tax credit; liability to pay tax; requirement for registration; and whether an act constitutes a supply under the Act.