What type of court document initiates a lawsuit?

The document that initiates a lawsuit is the complaint. A complaint is a formal legal document filed by a plaintiff to initiate a civil action. It outlines the plaintiff's claims against the defendant, specifies the basis for the court's jurisdiction, and seeks a remedy or relief.

When a complaint is filed, it sets in motion the legal proceedings and notifies the defendant of the claims being made against them. This process is essential in the judicial system as it establishes the issues that the court will ultimately decide.

Other documents, such as a motion, are used during the litigation process to request the court to make a ruling or order. An answer is a document filed by the defendant in response to the complaint, addressing the allegations made by the plaintiff. An affidavit is a sworn written statement of facts, often used as evidence in court, but it does not initiate a lawsuit. Thus, the complaint is the correct choice as it serves the crucial role of starting the legal process.