1If the cryptocurrency is using Bitcoin's proof of work algorithm, then mining is the only way to generate new coins. But I don't know enough about altcoins to tell you if there are other methods. – Matthew Cruz – 2019-11-29T10:56:56.333

Is it correct to say that the amount of bitcoins that globally miners can earn is pre-established in the blockchain code ? This is different from traditional currencies when the centralized coordinator can decide arbitrarily to create new money. Is right ? And, if i buy some bitcoins with my euro those same bitcoins where previously generated by miners. Correct ? – AleQuercia – 2019-11-29T16:40:13.243

1Yes the amount of bitcoin that will ever be created is just shy of 21million and it is in the Bitcoin Core code base. And yes all bitcoin are created by miners in the coinbase transaction and then held or put into circulation. As a note, when miners receive bitcoin from mining a block, they must wait 100 blocks until they can spend them. – Matthew Cruz – 2019-11-29T18:07:17.277