Black holes take unimaginably long periods or time to die. Even a black hole with the mass of the sun would take somewhere around 10⁶⁷ years to die. And all black holes are much larger that (assuming primordial black holes don't exist).
Black holes die by “evaporating". This is a necessary consequence of both relativity and quantum field theory.
The rate at which black holes evaporate is proportional to their temperature, called the Bekenstein-Hawking temperature.Eventually, in theory, black holes will evaporate through Hawking radiation. But it would take much longer than the entire age of the universe for most black holes we know about to significantly evaporate. Black holes, even the ones around a few times the mass of the Sun, will be around for a really, really long time!