Ravine Finder
Edition
Version
Seed
About one chunk in a hundred starts one, so there are usually several within a few hundred blocks of you.
Their walls cut straight through the stone, so the ores in them are out in the open: iron, coal, sometimes diamonds near the bottom.
On Java Edition, type /seed in chat (it needs cheats on, or operator rights on a server). On Bedrock, open the world's settings: the seed is listed under Game.