The Sun is a 4.6 billion year old yellow dwarf star at the center of the Solar System.
Although it’s a dwarf, compared to the Earth, the sun is huge. You would need to line up 109 Earths, side by side to equal the Suns diameter. It has the mass of 330,000 Earths.
It formed from a molecular cloud that collapsed under gravity, into a nearly perfect sphere, made of hot plasma.
It contains 99.86% of the mass of entire Solar System. The rest of the stuff flattened into a disk that formed the planets.
The center became so hot and dense that it initiated nuclear fusion.
It’s 73% hydrogen and 23% helium. The rest is a mix of heavier elements like carbon, oxygen, and iron, stuff that people are made of.