The USGA, in conjunction with The R&A in St. Andrews, Scotland, writes, interprets and maintains the Rules of Golf to guard the tradition and integrity of the game. The two organizations are joint authors and owners of the Rules of Golf and Decisions on the Rules of Golf. Through an agreement with The R&A, the rules jurisdiction of the USGA includes only the United States, its possessions and Mexico. The latest version went into effect on 1st January, 2019.
Please visit the below links for information:
R & A Resources:
Clarifications of the 2019 Rules of Golf – 1 January 2021
USGA Resources:
USGA Rules of Golf & Interpretations