If you’re unfamiliar with Vision, it is a diagramming and graphics app. It comes with the following features by default:
Create professional diagrams easily with ready-made templates and shapes Get started quickly with a familiar Office-like experience Use your finger or pen to draw and make notes more naturally on touch-enabled devices Create database visualizations using the built-in database model diagrams Collaborate with others by adding and replying to comments directly within Visio
Co-authoring on Visio works very similar to the feature on Office apps. You can see the edits made by co-authors. On Visio, the app will display a presence indicator so you know if somebody else is already editing the diagram. This ability means there will be no editing conflicts. Furthermore, users can add and replay to comments left by other users. Again, this is similar to Office co-authoring.
Availability
Real-time co-authoring is now available to users with the Visio Plan 1 or Vision Plan 2 subscription. Co-authoring is only available for these users, but even people without a Visio subscription can view and replay to comments made on a diagram. “Our goal is to make the way you work easier. This is yet another step in the journey of making Visio a more collaborative app that you can use to brew ideas and work seamlessly with others”. – Microsoft.