Which department should I look for to prove the conformity of the occupational health and safety management system certification of logistics companies?

If you have carried out safety evaluation or occupational hazard evaluation and passed the acceptance of relevant government departments, then the acceptance approval can be used as proof of compliance.

If you haven't done it, you can ask the local safety supervision department to issue a certificate, but it is very difficult. They are generally reluctant to issue such certificates because the risks are too great.