All the documents evolve according to a defined lifecycle. The default lifecycle is composed of the following states: Project, Approved and Obsolete. There are different ways to make documents evolve through this lifecycle. One of them is to use a workflow.
Users involved in workflows are alerted by email and can have a synthetic view of all their pending tasks on documents in their dashboard or on the Task tab. The documents they have to review are listed there.
A task represents what a workflow instance expects from a user or a group of users. Usually they are expected to give some information through a form and click on a button (like Accept, Reject, Confirm, Notify, Transform, etc.). A task usually has one or several assignees, a title, a directive and an expected date of achievement. The task assignees can be specified directly in the task definition or can be dynamically computed. If a task is assigned to you but you won't be able to perform it, you can delegate the task or reassign it.