Subpages that are removed from the navigation menu can still be accessed using direct links. However, if the subpage is hidden, it can no longer be accessed at all.
To remove the subpage from the navigation menu
In the left panel, hover over the subpage you don't want to show in the navigation menu and click Edit.
Select Don't show in navigation.
Click Save.
Note: You'll now see the
icon once a subpage is removed from the navigation menu. To put it back, just go through the same process but un-check the box on step number 2.