We all know the rules we play competitive chess under. They are the FIDE Laws of Chess. Our individual federations in different countries may tweak the parts of the rules they're allowed to tweak (the ECF, for instance, overrides the FIDE "zero tolerance" by saying that if an organizer doesn't specify a default time then for standard time control it is 30 minutes) but basically we play by FIDE's rules.
Who makes those rules? Every 4 years or so FIDE has a major revision of the rules. The last major revision was in 2017 with a tweak to rapid and blitz in 2018. We were due a major revision last year, delayed no doubt by Covid. We should expect a new revision soon. What kind of people are going to be making those changes?