I have upgraded from Ubuntu 16.04 LTS to Ubuntu 18.04 LTS. I was surprised to see that the context menu entry "Make Link" (keyboard shortcut Ctrl+M) in Nautilus doesn't seem to exist anymore. It used to appear upon right mouse click on a file or folder and allowed the user to create a symbolic link.
This answer is suitable for Ubuntu 18.04 LTS, since Ubuntu 16.10 the feature preference has changed. The feature still exists ... it just has to be activated. Open Nautilus and go to Preferences -> Behavior.
Enable the option "Show action to create symbolic links". Now you have the "Create Link" context menu entry in Nautilus ... Note : The keyboard shortcut changed from Ctrl+M to Ctrl+Shift+M.