Enable Workbench Moderation module.
The moderation workflow needs to be enabled for each content type. For example, to enable moderation of Basic pages:
- On the Administration toolbar, click Structure.
- Click the Content types link.
- Click the edit link in the OPERATIONS column for Basic page.
- Under Publishing options deselect Published and select Create new revision and Enable moderation of revisions.
- It is recommended you leave the Default moderation state as Draft: Visible only to the author.