Moodle is a modular system.
This means that Moodle was built to be able to include additional functionality to its core platform through the use of plugins. Anyone can create a plugin, and the Moodle Plugins Database is where official plugins can be searched and downloaded.
Moodle plugins allow users and organisations to extend and customise the functionality of Moodle beyond what Moodle HQ have developed for Core. This flexibility is what makes Moodle collaborative and community-enhanced.
A Moodle theme is a plugin which extends or enhances the appearance of your Moodle site. There are many popular themes on our Moodle Plugins Database that you can try out.
*If you want to contribute your own plugin, please refer to the article How to create a Moodle plugin.