The co-authoring features in Microsoft 365 Collaboration enable multiple users to edit and collaborate on a document in real-time. This functionality enhances teamwork by allowing simultaneous contributions, streamlining the editing process, and improving overall productivity.  Functions of co authoring include commenting, track changes and reviewing the document in among multiple users.

In the image shown below, the top right corner indicates that another user is collaborating on the document, as evidenced by their initials and the blue dot on the document indicates where the user is editing.

In the second image below, several users are actively utilizing the commenting feature within the document, akin to the functionality found in the Word platform.

In the event the user becomes idle while working on their document, the "Save and Refresh" will appear reminding the user to save their work and will display changes made by other users as well.

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Document Manager - Editing a Word Document with Microsoft 365 Collaboration