Moodle is a Virtual Learning Environment (VLE) that allows learning and teaching to continue outside of the classroom. It is not a program to replace face-to-face teaching, but to support it with a range of flexible online tools, as well as a place to find a module's learning resources.
In Moodle, every module you study will have its own webpage which lecturers can easily edit, giving you access to up-to-date information, announcements, copies of handouts/PowerPoint presentations and links to relevant external websites. They can also build in activities such as discussion forums, quizzes, questionnaires, chat rooms and wikis.
Moodle is open source software, which has been adopted by educational institutions globally, including The Open University.