What is a black hole?

A black hole is a place in space where gravity is so strong that nothing, not even light, can escape. It acts like a cosmic sinkhole, forming when a massive star collapses into a tiny, incredibly dense spot. Because light is trapped inside, they are invisible, often described as a dark, "bottomless pit" in space.

Once it achieves a stable condition after formation, a black hole has only three independent physical properties: mass, electric charge, and angular momentum; the black hole is otherwise featureless. There are three main types of black holes, stellar-mass, intermediate-mass, and supermassive.

Teacher, how are black holes created?

Well, when a massive star is at the end of its life the star will collapse into itself which can cause one of two things, a supernova or a black hole.

To get a better idea here is step by step to what exactly leads up to the creation of a black hole.

John Michell was the first to have proposed the existence of stellar bodies comparable to black holes, and was the first to apply statistics to astronomy, providing the earliest evidence for the physical nature of double stars and star clusters.

Stephen Hawking predicted that Black holes emit radiation due to particle-antiparticle pairs forming near the event horizon, leading to a loss of mass (evaporation), this study was called Hawking Radiation. He had another study where he predicted the total surface area of a black hole’s event horizon can never decrease, confirming a link to thermodynamic entropy.