i can't us material drop tool

As JJMack shows the 3D material drop tool is for putting 3d materials onto the surface of a 3D model.

Your screenshot shows you are working in 2D, but using the 3D workspace.

Go to the top right and from the drop down menu choose  "Essentials" to restore teh default workspace and toolbar

Dave

I just created a new 3d Sphere 3d layer from a mesh preset and use the Material drop too to change its surface texture.  You need to target a 3d layer and select a material preset.