The Moon always has a single face to us. Every time the Moon appears in the sky, we are looking at the same side of the Moon, just as if we were looking at the surface of a spinning object. The side we see changes over time, so the Moon doesn't look exactly the same.
It's believed that the Moon has at least one moon that has captured the Moon in orbit. Scientists believe that the Moon captured this moon when the gravity of this moon was stronger than the gravity of Earth. This may have occurred when this moon passed too close to the Earth, or when a collision with a planet made this moon a giant lump of debris.
Over time, the Moon has slowly rotated and became as it looks today. This is why you always see the same side of the Moon, just as if you are looking at a disk.