Why do we see different shapes of moon ?

because of rotation and revolution of earth

The phases change as the moon revolves around Earth, different portions of the moon's sunlit surface are visible from Earth. Thus, from the perspective of Earth, the appearance of the moon changes from night to night. Not only does the apparent shape of the moon change, its position in the sky also changes.

ahaha 8

my answer has to be at least 20 characters so here are the rest of the characters lol