1 Pa. Code § 33.35
There shall accompany and be attached to the original of each pleading, submittal or other document filed with an agency when service is required to be made by the parties, a certificate of service in the form prescribed by § 33.36 (relating to form of certificate of service). All other copies filed shall be fully conformed thereto.
1 Pa. Code § 33.35
This section cited in 16 Pa. Code §42.34 (relating to motions); 25 Pa. Code §1021.36 (relating to certificate of service); 25 Pa. Code §1021.91 (relating to general); 34 Pa. Code §111.12 (relating to filing, service and proof of service); 34 Pa. Code §111.14 (relating to motions to quash); 34 Pa. Code §121.34 (relating to objections to assessments); 34 Pa. Code §131.11 (relating to filing, service and proof of service); 34 Pa. Code §131.56a (relating to withdrawal of appearance); 37 Pa. Code §171.25 (relating to service); 37 Pa. Code §197.5 (relating to service on other parties); 37 Pa. Code §197.34 (relating to notice of appeal); 40 Pa. Code §15.44 (relating to service); 40 Pa. Code §17.13 (relating to protests/intervention procedure); 52 Pa. Code §1.57 (relating to proof of service); 52 Pa. Code §1001.55 (relating to proof of service); 55 Pa. Code §41.23 (relating to proof of service); 55 Pa. Code §41.24 (relating to certificate of service); 61 Pa. Code §703.5 (relating to other submissions); 61 Pa. Code §703.6 (relating to service); and 67 Pa. Code §491.8 (relating to service).