Answering the first question how black holes are formed which are incredibly dense objects with gravity so strong that nothing, not even light, can escape. The two types in which black holes are formed are:

1. Stellar Block Holes: When stars run out of  their fuels and  collapse under its own gravity. This collapse triggers a supernova, a massive explosion that scatters the star’s outer layers into space. The remaining core collapses into an incredibly dense object – a black hole. These are the most common type.
2. Supermassive Black Holes: These behemoths are found at the centers of most galaxies. Researches suggest it has two types of collapses that is ‘direct collapse’ which is massive gas clouds in the early universe collapsed directly into black holes without forming stars first. And another is ‘mergers of small black holes’ where Smaller black holes growing through accretion and merging with each other over time.

Coming to the second question about what will happen to it if matter falls into it; once the matter crosses the event horizon (the point of no return), it gets lost outside the universe. Scientists believe, ‘spaghettification’ happens that is the intense gravity of the black hole stretches objects (including light) into long, thin strands. Some believe, ‘accretion disk’ happens which is the matter swirls around the black hole before crossing the event horizon which forms a superheated accretion disk. Another phenomenon known as ‘singularity’ which is a point of infinite density where our current understanding of physics breaks down is also believed to happen.