If someone tells you "bon voyage!" they mean have a good trip. Voyage means trip in French but in English, we use it to mean a long journey.
Though voyage is usually used literally to mean a long and exciting journey or a trip that involves sailing such as a cruise, it can be used figuratively as well. Researching your family tree might become a voyage of self-discovery, taking you places you don't expect and teaching you more about yourself than you thought possible.