Appeal filing procedure: use Form GST APL-03 with supporting documents and obtain appeal number after certified order submission. Application to the Appellate Authority must be made in FORM GST APL-03 with supporting documents, filed electronically or by other modes as notified by the Commissioner. A certified copy of the decision or order appealed against must be submitted within the prescribed short period after filing, and the Appellate Authority or an authorised officer will generate an appeal number.