When you wish to edit a document that has been uploaded, it is a SharePoint best practice to use the check-out process. Checking out the document is not a necessary step for working on a document, but it is recommended because taking this step will prevent other users from interfering with your work by making sure that only one user is working on a document at a time.
Download the How to Check-out/ Check-in Documents guide to follow step-by-step instructions to check out a document and check it back in.
Note: Powerusers have the ability to check in any document to their document library, even if another user was the one who checked it out. We recommend consulting with the user who checked out the document first so the Poweruser does not inadvertently lose another user's work. But, in some cases it may be necessary to override another user’s checkout because they are away from the office or have left the team.