The moon is a natural satellite to the Earth,

We cannot say for sure as there is no complete evidence, but it’s believed that the moon was formed from left over pieces of a collision between the Earth and another object during the very early stages when everything was being formed in the solar system. So for about 4.5 billion years or so, the moon has been orbiting our planet, where they go hand in hand like a child and its parent. The moon is a natural satellite to the Earth, and all it means is that the moon orbits around the Earth naturally compared to man-made satellites. The moon orbits around the Earth in just over 27 days, and within that time there are different phases of the moon. Read more here

The Moon