The car purchase agreement is concluded by a person with full capacity for civil conduct. The contents of the agreement are true and legal, do not violate public order and good customs, and do not harm the legitimate interests of the state, the collective and others. If it has the main provisions of the contract, it has legal effect. Legal basis: According to Article 143 of the Civil Law of People's Republic of China (PRC), a civil juristic act that meets the following conditions is valid: (1) The actor has corresponding capacity for civil conduct; (2) the meaning is true; (three) does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs. The contents of a contract are agreed upon by the parties, and generally include the following terms: (1) the name and domicile of the parties; (2) Subject matter; (3) quantity; (4) quality; (5) Price or remuneration; (6) Time limit, place and method of performance; (7) Liability for breach of contract; (8) Methods for resolving disputes. The parties may conclude a contract by referring to the model texts of various contracts. Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it.