How to add 3D features in Online ArcGIS (Story Map) - I created the 3D layers / features using ArcMap Desktop and ArcScene
I'm a student and a newbie looking for detailed information.
A quick search uncovered Make your first scene in the ArcGIS Online Help:
A scene is symbolized 3D geospatial content that includes a multiscale basemap, a collection of 2D and 3D layers, styles, and configurations that allow you to visualize and analyze geographic information in an intuitive and interactive 3D environment.You can create scenes with the built-in scene viewer or with ArcGIS Pro. To create scenes, you need to be signed in with an organizational account or a public account.
and blog postings called:
These seem to be geared around ArcGIS Pro rather than ArcMap/ArcScene as your authoring tools but I think you should be able to open the items that you have authored in ArcMap and ArcScene in ArcGIS Pro.