The publishing approval workflow is enabled by default when you create a publishing site. The workflow automatically routes web pages, assigns review tasks and tracks their progress, and sends reminders and notifications to approvers when necessary.
A publishing approval workflow is similar to other SharePoint workflows in that it automates the routing of content to subject matter experts and stakeholders for review and approval. What makes the publishing approval workflow unique is that it’s designed specifically for publishing sites where the publishing of new and updated web pages is tightly controlled. In these kinds of sites, no new content can be published until it has been approved by every approver in the workflow.