Serving Legal Papers in California [English]

https://www.courts.ca.gov/selfhelp-se...
"Service of court papers" means that the other side must get copies of any paper you file with the court. In “service” a third person (NOT you) is the one who actually delivers the paperwork to the other side. The person who does this is called the “server” or “process server.”

Until the other side has been properly "served," the judge cannot make any permanent orders or judgments. [English]
The law says that when you sue a person, partnership, corporation, or the government, you must give formal notice to the other side that you have started the legal process. This video walks you through the process of serving.

www.courts.ca.gov/selfhelp-serving.htm