A Pennsylvania Subpoena is a legal document issued by a court or other government entity to compel an individual or entity to appear to testify or produce documents in a legal proceeding. There are two types of Pennsylvania Subpoenas: a Subpoena Ducks Cecum, which orders a witness to produce specific documents, and a Subpoena Ad Testificandum, which orders a witness to testify at a hearing or trial. In Pennsylvania, a Subpoena may be issued by the court or by a party in a case, and must be served to the witness before it can be enforced.