Documentation on enabling web services: https://docs.moodle.org/33/en/Using_web_services Enable web services Enable XML-RPC protocol Enable the "Web services authentication" plugin (site administration > plugins > authentication > manage authentication) Add capability webservice/xmlrpc:use to authenticated user role Create a new WS with necessary functions (see #2) and a token Use Web services test client to call a WS function using XML-RPC , try both simple and token authentication (Site administration > Development > Web service test client) P.S. create_course_category for some reason does not work with parent=0, use parent=1 (fixed in MDL-60091 master-only)