Legally, forgery should be proved through judicial procedures, but whether it can be proved depends on whether there is evidence. For the authenticity of the signature, you can apply to the court for judicial expertise in written form after entering the judicial process, or you can seek the third-party appraisal agency to conduct self-appraisal. When entrusting judicial expertise by oneself, it is usually carried out through a law firm. This handwriting can still be authenticated, and then the judicial expertise results can be accepted by the court. Forging a contract is a serious crime and should be investigated by law. Article 2 of the Contract Law of People's Republic of China (PRC): Agreements between natural persons, legal persons and other organizations with equal subjects to establish, change and terminate civil rights and obligations. Other laws shall apply to the agreements on identity relations such as marriage, adoption and guardianship.