[da_chicken]

Dungeon World is a Powered by the Apocalypse game. It's both ligher in rules and gives the players increased control over the narrative of the game. It's a narrative TTRPG. If you've played FATE or Blades in the Dark you've played a narrative RPG.

Dungeon World is an open game and there is an SRD for it: https://www.dwsrd.org/

In the case of falling, the GM would assign damage based on how dangerous it is: https://www.dwsrd.org/playing/playing-the-game.html#damage

Bear in mind that HP essentially doesn't scale with level. PCs are likely to have an HP maximum between 15 and 25 for the entire campaign.

If you're conscious, the GM might let you Defy Danger to mitigate some of that, but you have to describe what your character is doing to achieve that: https://www.dwsrd.org/playing/basic-moves.html#defy-danger

If it was a fall from a great height, you'd just skip to Last Breath: https://www.dwsrd.org/playing/special-moves.html#last-breath

There's no specific rules for it because the general rules are good enough, especially considering how often falling damage actually comes up