How to create UI Sprites in 3D worldspace? Like in Untitled Goose Game

Hello, I need to create sprites that appear and disappear in a 3D game, like the exclamation mark that appears on the boy's head in Untitled Goose Game.

I tried to save the UI canvas as a prefab, and instantiate when conditions are met. But the canvas settings are wrong when initiated. Also, how can I get the exclamation mark stay along when the player moves while facing the camera all the time?

This seemed like a very simple task, but when really implemented can get very complicated, or is there any method that I have missed?