A world championship is generally an international competition open to elite competitors from around the world, representing their nations, and winning such an event will be considered the highest or near highest achievement in the sport, game, or ability. How the championship title is assigned. The title is usually awarded through a combination of specific contests or, less commonly, ranking systems (e.g. the ICC Test Championship), or a combination of the two (e.g. World Triathlon Championships in Triathlon).
https://en.wikipedia.org/wiki/World_championship