Stage requires heavier makeup as well as TV (due to the stage lights), where as film can be lighter. Although this does not cover the dramatic or face altering character makeup.
No one has to wear makeup, The choice in yours. You can choose to, or you can choose not to.
If you're a singer, actor, or other performer, you need makeup to keep from looking dead on stage....
This is something you should see rather than just be told. So...either go to a website like covergirl-dot-com or maybelline-dot-com where they have videos, check out youtube's makeup gurus, or just...