The rules of chess have varied over time and various authors have written them down over the centuries.
Philidor is most often credited for formalising the rules for tournament use, however the problem still remained that there were no common set of rules accepted by everyone.
In the 1920s FIDE was formed, and there was an attempt to standardised the rules. This was successful to to a degree, however different interests still maintain their own rules: for example the English Chess Federation base their rules on the FIDE rules but with some modifications, and some tournaments or matches may add their own rules e.g. The Sofia Rule.
There is therefore no universal set of rules, but the FIDE rules are use in FIDE organised tournaments, which are most of the top level ones. Minor changes are made to these every so often. Mostly these are to clarify existing rules but occasionally you get new rules such as the ones forbidding 'note taking' and those prohibiting the use of electronic devices which have been added relatively recently.