the testimony is to be given to serve the subpoena on the witness. If a witness is reluctant to testify, then the personal service of subpoena is usually required with proof of service by non-party server.

The subpoena will usually be on the letterhead of the court where the case is filed, name the parties to the case, and be addressed by name to the person whose testimony is being sought. It will contain the language "You are hereby commanded to report in person to the clerk of this court"