When people are working on one document in a SharePoint document library, the SharePoint co-authoring feature makes people collaborate and work easily. With the co-authoring feature, one author can edit his content and another author can edit hers, and they can see the changes of each other in real-time.
There are two kinds of SharePoint co-authoring, regular co-authoring and real-time authoring. The big difference is that when you will see the changes made by others in the document.
For regular co-authoring, you will see an Updates Available status in document when new changes are made. When you save the document, you can see the changes.
For real-time co-authoring, you can see the cursor location, and what others type on the document. Every changes happen in front of you.
When using co-authoring feature, you should consider these tips:
Disable Check-out: The check-out feature ensures that only one person can edit the document at one time. When a document is checked out, the others cannot edit the document unless it is checked in. So, disable check-out feature in document library if you plan to use co-authoring.
Turn on versioning: Turn on at least major versioning in document library, in case of mistakes or accidents happen during edit document process.
Author permissions: Ensure that all co-authors have the permissions to edit the document.