Moodle is an open-source learning management system (LMS) that is used by educational institutions and companies for e-learning and online training. It provides features like content uploading, tracking, discussion forums, and customizable looks. While Moodle is free to use, organizations need to invest in hosting, customization, reporting, course set-up, training, and potentially bespoke modules. Support is available through an active community on the Moodle website.