There are two types of eclipses. It is solar eclipses and lunar eclipses. The solar eclipses are the Moon shadow the Earth and the lunar eclipses are the Moon passes the Earth shadow. The position of solar eclipse is Sun, Moon and Earth in straight line. The lunar eclipse is Sun, Earth and Moon must be in a perfectly straight line.
The solar eclipses are the Moon passes between the Earth and the Sun so that you cannot see all or part of the Sun for a time. We see at the Earth some part of the Sun's disk covered by the Moon. You might think New Moon occurs every 29.5 days so we should have solar eclipses about once a month. But that is not true because the Moon's orbit around Earth is tilted five degrees to Earth's orbit around the Sun. The solar eclipses have total solar eclipses and partial solar eclipses. The path of a total eclipse can cross any part of Earth. The total solar eclipses are you can't see all the Sun and The partial solar eclipses are you can't see the part of the Sun. The next solar eclipse is at Tuesday, 21 December.