This article explains how to create a simple document approval workflow using SharePoint 2013.
Open the SharePoint site.Create the Document Library.Click on workflow settings.Select the Workflow association type as “Document”.Click on Add a workflow.Select the approval workflow then provide the name for the workflow, “Approval Status”.Create a new task list for this workflow.Uncheck Allow this workflow to be manually started.Check the box Create a new item will start this workflow.Click Next.Provide the approvers for this workflow.Provide the document request message.Check “Automatically reject the document if its rejected by any user”, so it will reject the document if it's rejected by any one of the users.Check “Automatically reject the document if it change before the workflow has been completed”, so the document has been rejected when the user has been deleted or changed.Click Save.So now you can see the simple Approval Workflow has been created.Now open the Document Library to upload the document.Now you see the Approval status has been InProgress.Now login as approvers username and password to approve the tasks.Enter your comments and click approve or reject.After approval of both from both users you can now see the status of the document.So the document has been approved successfully.If you need to read the comments provided by the approver click on the approved status link
SharePoint Online And Office 365 Administration