Managing zoom in unity default camera?

what is zoom exactly for the unity default camera, Im not able to comprehend simple scaling at all. I have assets which handle this, but Im trying to go back to basics and learn unity 2D UI stuff from scratch.

the camera doesnt scale as I thought it would.

The camera doesnt affect the UI per default. The size of the GameView is what determines the position and size of the Canvas that they’re rendered on. You can however change the render mode into “world” and it might be possible to do somethig more exotic with the camera there.