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:
Invite, remove and manage workspace Member permissions.
Change the workspace's functionality. If you remove a feature from a workspace it is only hidden from workspace members view, it's content isn't deleted. It can be re-enabled at any time and all of it's content will be intact.
Select a default settings for files, posts and tasks. Archive or delete workspaces.
This User Activity Report records all activity associated to files, discussions, tasks and announcements, across the workspace.