At the user level, you can expand or collapse Module content from your personal view, but not for other course members.
Open Modules
In Course Navigation, click the Modules link.
Collapse Module Contents
Click the Expand/Collapse arrow. This will only hide the module contents from your personal view.
View Module
The module content will stay collapsed until you decide you show it again. You can show module contents by again clicking the Expand/Collapse arrow.