I need to search for some pictures taken from angle like below picture. what do you call this viewpoint or position the photo is taken from?
From the perspective of the photographer or cineast, this viewpoint is often called an over the shoulder shot.
In cinema, directors such as Orson Welles used it to develop empathy with the character. Often seen after an "establishing shot" to show dialogue from the viewpoint of the main character, the image is framed with the back of the head and shoulders.
It is also used after a "creeping up" or "watcher shot" to heighten tension.
See this site for more information on all "Shots with a Special Narrative Significance".