Every pleading shall contain a caption setting forth the name of the court, the number of the action and the name of the pleading. The caption of a complaint shall set forth the form of the action and the names of all the parties, including a Doe designation for an unknown defendant as provided in Rule 2005, but in other pleadings it is sufficient to state the name of the first party on each side in the complaint with an appropriate indication of other parties.
231 Pa. Code r. 1018