Primordial black holes are believed to have originated in the very early universe, just seconds after the Big Bang. In specific circumstances, regions of dense material could have collapsed into black holes of different sizes. Some might be immensely small, at the same time, others could be even larger than the Sun.
Presently, there is no significant evidence that primordial black holes exist, considering they may have evaporated through the period. In contrast, more massive primordial black holes could still be out there, and scientists have been keen on exploring this possibility.