Bitcoin mining is the process of verifying transactions and adding them to the blockchain. Miners solve complex mathematical puzzles through a process called Proof-of-Work. The capacity to solve this puzzles is measured in hashing power (Terahashes per second, or Th/s).
The first miner to solve the puzzle gets to add a new block to the blockchain and is rewarded with newly created Bitcoins and transaction fees. Mining is resource-intensive and decentralized, involving individual miners or mining pools that distribute the rewards among all their participants.