Why does my text object look weird along its edge? I am new to blender, and after I created a text object, I found it had a black material along its edge.

Here is view display and render display, which shows the problem. I don't know understand what is causing this. It looks unrealistic and bad—is there any way to beautify it?
Sadly it's because of default Smooth shading (Normals) on extruded part of Text object. 



You can fix that by adding Edge Split modifier.



Or you can search Convert to Mesh and enable under Data Properties > Normals > Auto Smooth. But you would not be able to retype your text.