Why does the moon takes on different shape?

The Moon takes on different shapes, or phases, due to its position relative to the Earth and the Sun. As the Moon orbits the Earth, varying portions of its surface are illuminated by sunlight, creating the phases we observe, from new moon to full moon. This cycle lasts about 29.5 days, during which the Moon appears to change shape in the sky. The primary phases include new moon, crescent, first quarter, gibbous, full moon, and then back to new moon.