Hello! If you know the policy number, you can log in to the insurance company official website to inquire about the policy, you can also call the insurance company's customer service hotline to inquire about the policy information, and you can also take the policy, ID card and other materials to the insurance company for counter inquiry business. However, you only have the other party's policy number here, and you can't query other people's policy information without querying the password. When dealing with the traffic accident compensation issue between the two sides, it is suggested to notify the public security department first, and then solve the problem through formal channels and reasonable channels.
Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.