What legal document is issued to start a proceeding against someone in a lawsuit?

The legal document that initiates a lawsuit against someone is known as a complaint. This document serves to formally outline the plaintiff's allegations against the defendant, specifying the facts of the case and the legal basis for the claims being brought forward. The complaint sets the stage for the court proceedings by notifying the defendant of the issues they must respond to, thereby establishing jurisdiction over the case and providing a framework for the legal arguments that will be presented.

In contrast, a subpoena is a command for a person to appear and testify or produce evidence in a legal proceeding, not a document that starts a lawsuit. A demand letter is typically sent prior to a lawsuit being filed, urging the opposing party to take action or settle the dispute outside of court. An appeal, on the other hand, occurs after a trial has concluded when one party seeks to challenge the decision made by a lower court. Each of these documents serves a distinct purpose in the legal process, but the complaint is uniquely essential for commencing legal action.