2.2.1 Working with files
3. Instruction
3.4. Providing resources via an external repository
If this option has been enabled by your administrator it is possible for users to use external repositories to copy or create a shortcut or alias to their files in repositories such as Dropbox, Google Drive or Microsoft's OneDrive. For a full list of all the repositories that can be used with Moodle see Managing repositories in Moodle docs.
The Moodle site administrator has to install some plug-ins and fiddle with some other stuff. Instructions on how to do this for the more common repositories can be found here: