The commission shall prescribe the rules of procedure and the rules for the taking of evidence in all matters that may come before it. In the investigation, preparation, and hearing of cases, the commission shall not be bound by the strict technical rules of pleading and evidence but may exercise such discretion as will facilitate its efforts to ascertain the facts bearing upon the right and justice of the matters before it. When deemed necessary, in all formal cases heard and determined, the commission shall render an opinion setting out the issues involved in the case and its decision, ruling, and findings thereon. The commission is authorized to provide by rule and regulation for the procedure to be observed in the rehearing, reconsideration, and oral argument of all orders entered by the commission.