All characters in this game have one Passive that’s unlocked as soon as they’re collected, and a few others that will unlock as that character ascends to Phase 2 and so on. A ton of them are negligible like “the time this character takes on certain Expeditions in Mondstadt is reduced.”
But, there are some that are insanely useful for the open-world exploration sections of the game such as Amber, Venti, Ningguang, Qiqi, Klee, Kaeya, and Beidou. The things these passives do can range from marking Ore on the mini-map (which helps with farming things like White Iron) to reducing the stamina cost of running, gliding, or swimming.