Mining is how new blocks get added and new bitcoin gets issued. Miners use specialized computers to compete for the right to add the next block, and the winner gets paid in bitcoin.
Go deeperMiners race to find a number that makes the block's hash meet a target. It takes real electricity and hardware, which is why it's called proof of work. Every 2,016 blocks (about two weeks) the difficulty adjusts so blocks keep coming about every 10 minutes, no matter how many miners join.