Moodle is a learning management tool. It has a GNU GPL "free distribution" license programmed in PHP. Its purpose is to help educators create an online learning community. Currently, it is the main tool for both schools and universities, but it is also being used as a platform for online courses.
Currently, Moodle can run on both Windows and Linux servers.
Among the most notable figures for Moodle, according to the year 2017, we can find:
90,598 registered websites with active Moodle installations.
Active in 233 countries around the world.
14,107,382 courses taught.
120,529,557 registered users.
In conclusion, after seeing these latest numbers, we can conclude that Moodle is one of the best alternatives if we want to use an online training system. Whether it is for courses.