A new moon is when the moon is not visible from Earth, this happens when Moon is directly between us and the sun, the part facing us does not receive sunlight, and we cannot see the moon.

A Full moon is when the entire face of the moon is illuminated by the sun, this happens when moon is halfway through the moon's phase cycle as the Earth is directly between the sun and the moon

Different Moon Phases. The moon phase cycle begins with a new moon. The moon goes through eight phases in a cycle that repeats every 29.5 days.