Legal basis: Article 20 of the "Several Provisions of the Supreme People's Court on Evidence in Civil Litigation" When applying to the People's Court for investigation and collection of evidence, the parties and their litigation agents shall submit a written application before the expiration of the time limit for producing evidence. The application shall state the name, unit name, residence and other basic information of the person under investigation, the name or content of the evidence to be collected under investigation, the reasons for the people's court to investigate and collect the evidence, the facts to be proved and clear clues.