What creates a black hole in space?

A black hole forms in space when a very massive star (at least 3 times the mass of our Sun) runs out of fuel and can no longer support itself against gravity. After exhausting its nuclear energy, the star collapses under its own weight. If the core’s gravity becomes strong enough, it compresses all the matter into an incredibly tiny, dense point called a singularity, where gravity is so strong that not even light can escape.

In short:

Massive star dies → Core collapse → Extreme gravity → Black hole forms.