Hi @ABBS
I will assume that you already have a DEM layer. If you don't, you can extract one from the Esri terrain layer in ArcGIS Pro using the Export Raster pane.
I also assume you are looking to map a circular area, since you mentioned a radius. You first need a polygon layer representing this area. Here's how you can make one:
1. Insert Point Map Notes.
2. On the ribbon, on the Edit tab, click Create. Use the Create Features pane to draw one point in the middle of the area you want to map.
3. Save your edits. Clear the selection.
4. Open the Buffer geoprocessing tool. For Input Features, choose the Point Notes layer. For Distance, specify the radius you desire.
You now have a polygon representing your mapping area.
Next, you need to clip the elevation layer to the circle:
5. Open the Clip Raster geoprocessing tool. For Input Raster, choose the DEM. For Output Extent, choose your the new polygon layer. Check Use Input Features for Clipping Geometry.
Another new layer is added to your map. Turn off the other layers. You now have a circular DEM.
6. To turn the DEM into a hillshade (or other elevation visualization, like slope, contours, aspect), open the Raster Functions pane. Under Surface, click Hillshade.
7. For Raster, choose the newly clipped raster. Click Create new layer.
To learn more about visualizing elevation layers with raster functions, see this lesson: Illuminate terrain with a custom hillshade
Note that the results of raster functions are temporary. To make the results permanent, use the Copy Raster geoprocessing tool to save a copy.