Disabling right click is a stupid way of protecting one’s content. If your browser able to read the content, so does the user. The user able to download / copy or do whatever they want to do. That’s a fact!
However if you are a Moodle user, you may notice ‘Save Video as’ option on Chrome for your videos as annoying.
There is many other suggestions such as embedding the content using iFrame etc to prevent content download. However such method will prevent users from using offline reading feature in Moodle mobile.
So here is a simple way of preventing right click on your Moodle site;
Go to Site Administration => Appearance => Additional HTML
Add the following code in When BODY is opened section;