Can I add custom functions to openxr?

I want to add the conference function to openxr. Do openxr have any extension interfaces that can be used? Then I can implement the conference function through the interface

OpenXR tends to be a lower-level interface: conferencing (shared experiences?) is a higher level capability that might be built on OpenXR but isn’t necessarily at the runtime level. That said, please see Khronos OpenXR Registry - The Khronos Group Inc for details on how to propose an extension. In order to implement one, you’ll either need to have your own runtime, or implement your extension as an API layer.