Hi. I hold a Bachelors degree in Criminal Justice Administration. I graduated Magna Cum Laude. I have prior high school tutoring experience.
Subpoenas are usually issued by the clerk of the court (see below) in the name of the judge presiding over the case. Additionally, court rules may permit lawyers to issue subpoenas themselves in their capacity as officers of the court. Typically subpoenas are issued "in blank" and it is the responsibility of the lawyer representing the plaintiff or defendant on whose behalf 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.
Subpoenas are issued when witnesses are being called to testify in court.
Summons are issued when defendants are required to appear in court for legal matters.
Hope that helps.
Please let me know if you need any further assistance. Thank you.