The original of every document filed with the Commission and required to be served upon all parties to a proceeding shall be accompanied by a certificate of service signed by the party making service, stating that such service has been made upon each party to the proceeding. Certificates of service may be in substantially the following form:
I hereby certify that I have this day served the foregoing document upon [all parties of record or name of person(s)] by [mailing, delivering to courier or delivering in person] a copy to each such person.
Dated at, ___ this ___ day of ___ 19 - .
(Signature)
(For)
[Rule 117.]