The Layer page in the Properties window for a base, post, classed post, grid values, contour, color relief, vector, peaks and depressions, point cloud, watershed, 3D wireframe, viewshed, or graticule controls the opacity of the entire map layer. Surface maps do not have a Layer page.
Adjust the Opacity of the entire layer on the Layer page. This example shows the Layer page of a contour map in the Properties window.
Change the opacity of the entire layer by entering an Opacity value from 0% (completely transparent) to 100% (completely opaque). Alternatively, click and drag the to change the opacity percentage.
3D surface maps do not have the ability to change the opacity for the entire map.