PROOF OF SERVICE
A proof of service is a court paper filed by a process server as evidence that she served the witness or party to the lawsuit with the court papers she was instructed to serve.
It is also required that other case documents filed with the court, such as motions, briefs, status reports, etc., be given or mailed to all parties. The copy filed with the court is usually required to have an accompanying proof of service by the person who gave or mailed the document to the parties. It is usually sworn to under penalty of perjury.