|Photo Credit: Bitcoin Detector|
Bitcoin mining is intentionally designed to be resource-intensive and difficult so that the number of blocks found each day by miners remains steady (currently 12.5 bitcoins generate every 10 minutes and it reduces to half every 4 years, so in 2021 it would be 6.25 bitcoins).
This both serves the purpose of disseminating new coins in a decentralized manner as well as motivating people to provide security for the system.
Bitcoin Miners who solves the complex problem get that reward (12.5 bitcoins). Every 10 mins a new block generates on the blockchain of bitcoin. So the miner are the super computer that are solving the hash codes.
Bitcoin mining is so called because it resembles the mining of other commodities: it requires exertion and it slowly makes new currency available at a rate that resembles the rate at which commodities like gold are mined from the ground.
See this infographic to learn more about bitcoin mining.