Filing a lawsuit (often called a plaintiff’s petition or complaint) generally requires the plaintiff to file a document (often electronically) in the general form required by the rules of procedure in the applicable state or federal court system, and to pay a filing fee. The petition or complaint must give the defendant (person or entity being sued) reasonable notice of the legal claims asserted and the factual basis for those claims.

In Missouri, initiating a lawsuit involves the plaintiff filing a petition or complaint with the appropriate court. This document outlines the legal claims and the factual basis for those claims, providing the defendant with reasonable notice of the case against them. The Missouri Rules of Civil Procedure govern the form and content of the petition, which typically includes the plaintiff's allegations, the legal grounds for the lawsuit, and the requested relief. The plaintiff must also pay a filing fee, which varies depending on the type of case and the court. Once filed, the plaintiff is responsible for ensuring that the defendant is properly served with the lawsuit, which allows the court to obtain jurisdiction over the defendant. Electronic filing (e-filing) is widely used in Missouri courts, and in many cases, it is mandatory. The specific procedures and requirements can differ based on the court's local rules, so it is important to consult those rules or an attorney for guidance tailored to the particular jurisdiction and type of case.