Version 5.6 of concrete5 introduced a useful, single-step workflow. Create workflows within the Dashboard, and attach them to certain permissions, and you make it possible for certain actions to require the sign-off or approval of certain users or groups, before those requested actions complete. Single-step workflow is included in concrete5, with multiple step workflow available as an enterprise add-on
Workflow is an extension to the powerful permissions model detailed in this documentation. It's possible to make any permission into a workflowable permission, and create actions that can be queued up as workflow requests. Read on for more information.