Process may be served on a resident or nonresident individual by (1) delivering a summons and a copy of the complaint to the defendant personally; or (2) sending a summons and a copy of the complaint by registered or certified mail, return receipt requested, and delivery restricted to the addressee.
You appear and answer by filing a written answer with the same court where the complaint was filed and serving the plaintiff with that answer.
A proof of service is, in almost all instances, required to be attached to documents that you are filing with the Court. This document is “proof” to the Court of the “service” you completed for the document you are filing.
In California, The most common methods include personal service, where a registered process server personally hands over the court papers to the defendant.
Serving Documents in an Existing Case Mailing a copy by regular mail to the address they gave in their court documents. Handing a copy to them in person. Leaving a copy at their home with an adult who also lives there.