A solar eclipse is caused when the moon passes between the Earth and the Sun, causing the Sun to be fully or partiall covered. Every year, at least two to five solar eclipse occurs.

There are four types of solar eclipses:
-A total eclipse occurs when the Sun is completely obscured by the Moon. The intensely bright disk of the Sun is replaced by the dark silhouette of the Moon, and the much fainter corona is visible. During any one eclipse, totality is visible only from at most a narrow track on the surface of the Earth.

-An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or

annulus, surrounding the outline of the Moon.

-A hybrid eclipse (also called annular/total eclipse) transitions between a total and annular eclipse. At some points on the surface of the Earth it is visible as a total eclipse, whereas at others it is annular. Hybrid eclipses are comparatively rare.

-A partial eclipse occurs when the Sun and Moon are not exactly in line and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the

umbra never intersects the Earth's surface, passing above the Earth's polar regions.

And here's a video from Jakarta about on a solar eclipse:

and an explanation on why solar eclipse can only be seen in some countries: