What is the most secure way to send my passport via post in Thailand?

The conversation provides advice on the secure ways to send passports via post in Thailand, recommending services like EMS (Express Mail Service) and Kerry Express, both of which are trackable. Several comments express concerns about sending passports to unlicensed agents, suggesting that if one must use an agent, it is safer to hand it directly to them instead of posting. Participants share their experiences with EMS and raise points about the risks of using questionable visa agents.