Hi Mike_peter_LearnArcGIS123S,
As far as viewing goes in Extended Realities (AR, VR & MR), I do not believe ESRI have an official application / workflows. Most applications are in Esri labs or in early adopter programs.
For AR, you can have a look at AuGeo which allows you to publish a WebMap (linked to your Feature Service) to a mobile application for AR viewing.
For VR, you can look into ArcGIS 360 VR. GIS Data is published into a City Engine viewer and can be deployed to the ArcGIS 360 VR application. Here's a link to the quick start documentation https://community.esri.com/t5/esri-labs-documents/arcgis-360-vr-quick-start-guide/ta-p/918595/jump-t...
I am not too sure about the progress of MR.
As far as I am aware, these applications are for viewing.
Hope this helps 🙂