How to convert world position to screen position in world unit?

Question

Unity

I have a canvas screen space camera. I need to display the ui over the coordinates in the world so that it is in the canvas in the panel.
This is how it doesn't work:

Vector3 screen_pos = cam.WorldToViewportPoint(pos_world);
this.transform.position = screen_pos;

Answer 1

Because you wrote stupidity, you converted it to "let's say so in screen" and for some reason put it back into world coordinates.