This short post shows you where to set the versioning so that the user must check out the document if they want to edit. Once they check in then they document needs to be approved.
Go to Library Settings on your Document Library.
Choose Versioning Settings.
Choose Yes under Require content approval for submitted items?
Choose Require document to be checked out before they can be edited? To Yes.
User need to Check Out and Check In when editing the document.
The Document Library owner can approve the document checked in,
By choosing Approved to approve the version
every time someone edits a document.