Navigate to the relevant workspace and click on the 'Options' link on the side navigation.
In the workspace 'Options' section you can do the following:
Users
Invite, remove and manage workspace Member permissions.
Groups
Create and manage groups to apply restrictions to individual folders.
Features
Change the workspace's functionality. If you remove a feature from a workspace, it is only hidden from workspace members' view; its content isn't deleted. It can be re-enabled at any time, and all of its content will be intact.
Settings
Select default settings for files, posts and tasks. Archive or delete workspaces.
Activity
This User Activity Report records all activity associated to files, discussions, tasks and announcements, across the workspace.