Solar Eclipses
A solar eclipse is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and when the Moon partially or fully blocks the Sun.
A picture of a total solar eclipse.
Kinds of Solar Eclipses
There are many kinds of solar eclipses. 
Partial-When moon partially covers the sun’s disk and casts only a special kind of shadow down onto the Earth.
Annular- When the moons disk is not big enough to cover the suns disk and the outer edges of the sun remain visible to form a ring that looks like fire, in the sky.
Total- When the moon completely covers the sun, you can see a total solar eclipse if you’re in the place and path where the moon casts its darkest shadow.
Only visible from in the part on Earth where the shadow of the moon falls, and the closer you are to the center of the path of the shadow, the bigger the eclipse appears to be
For a solar eclipse to take place, the moon, sun and Earth must be aligned together in a perfect or near perfect straight line that astronomers call ‘syzygy’. It happens around New Moon every lunar month.
Our moon is the right size, when it passes in front of the sun, it exactly covers the sun’s central disk, letting the corona shine out around it. The two bodies aren’t the same size, the sun is times the diameter of the moon, but it’s 400 times farther away from us, so it appears to be the same size.
The motions of the sun, moon and earth are brought into the correct placement once every 18 months.
Sources/citations
https://www.timeanddate.com/eclipse/solar-eclipse.html https://eclipse2017.nasa.gov/eclipse-who-what-where-when-and-how https://en.wikipedia.org/wiki/Solar_eclipse