The name black hole implies a region in space absent of anything, including light. This could not be farther from the truth. First predicted by Einstein's theory of general relativity, a black hole is a small super-massive and super-dense point in space consuming anything that gets close. There are a few ways that black holes can be formed, from gravitational collapse or from a high energy collision of two stellar bodies. When a massive star nears the end of its life time it begins to exhaust its fuel, eventually it will not generate enough pressure inside of itself to counter the gravitational force from its mass, when this happens the star will then collapse in on itself to a small point (some say this point is infinitly small and dense other say it is not, but it is not actually known the nature of this point). In a stellar collision when two celestial bodies are caught in eachothers gravitational wells they will begin to circle each other until eventually colliding creating a dense enough point that could facilitate the creation of a black hole.

Supermassive black hole Messier 87 [1]        Great video by Kurzgesagt explaining black holes [9]