Advance ruling clarifies tax treatment for proposed supplies, provided by designated Authority or its Appellate Authority. Advance ruling is a decision provided to an applicant on questions regarding the supply of goods or services being undertaken or proposed by the applicant. The scheme establishes the Authority for Advance Ruling to receive applications and render decisions, and an Appellate Authority for Advance Ruling to hear appeals. 'Applicant' includes persons registered or seeking registration under the Act, and 'application' denotes the request made to the Authority under the applicable provision.