Bitcoin mining is the process by which computer hardware performs mathematical calculations to the Bitcoin network to confirm transactions and enhance security.
This is how new bitcoins are generated.
There are a lot of people who don't understand how bitcoin mining works, so I'll try to explain it simply.
Mining involves solving a mathematical problem using a computer running software that does so. It requires a large amount of processing power, electricity and time.
When miners successfully solve the problem, they are rewarded with bitcoins (currently 12.5 bitcoins per block). It's like making money because when you solve a problem you automatically get bitcoins as a reward - which you can then resell or keep as an investment. The more processing power you have, the more likely you are to get lucky and solve the next problem first - which means more bitcoin rewards!