"Every ten minutes, a new Bitcoin block is created by Bitcoin miners, which is a subgroup of the people running computer nodes that keep Bitcoin operational. Powerful computers store all Bitcoin transaction data and update it as new transactions are added. Mining nodes are needed to verify transactions, and miners are rewarded for this with Bitcoin. Each new block of data (verified Bitcoin transactions) rewards the miners with 12.5 Bitcoins at the moment, meaning 1800 Bitcoins are created each day – but that won’t always be the case."
https://www.ccn.com/only-another-four-million-bitcoin-will-be-mined-heres-why/