Service by mail is a substitute delivery of litigation documents to give the opposing litigant notice of the suit against them by mailing the documents to the party or parties requiring service. In federal court, Federal Rule of Civil Procedure Rule 5(b) allows service by mail by “mailing it to the person’s last known address—in which event service is complete upon mailing.” States may also have analogous statutes allowing service by mail. For example, California Code of Civil Procedure § 1013 provides that, for service by mail, “the notice or other paper shall be deposited in a post office, mailbox, subpost office, substation, or mail chute, or other like facility regularly maintained by the United States Postal Service, in a sealed envelope, with postage paid, addressed to the person on whom it is to be served, at the office address as last given by that person on any document filed in the cause and served on the party making service by mail,” or “at that party's place of residence.” It also provides that service is complete at the time of deposit.
[Last updated in April of 2021 by the Wex Definitions Team]