Upon receipt by the clerk of any application, petition, notice of appeal or other instrument initiating a hearing, the same shall be referred to the administrative body which shall set a date, time and place for a hearing; provided, however, that the administrative body may authorize its clerk to set a date, time and place for a hearing upon receipt of specified instruments. Notice of hearings shall be given to the initiating party and to all other parties to whom notice is required by law to be given.