In simple terms, "cryptocurrency" is simply electronic money, funds, a virtual asset. They are not produced in physical form, but exist only on the Internet. They do not belong to anyone, they do not have a body that would administer them.
Note that any cryptocurrency can be exchanged for real money (rubles, dollars) through special services called exchangers (we will talk about them a little lower). There are no problems with this. The exchange for money is fast and without cheating. Rumors that crypto money cannot be exchanged for the money we are used to (euro, dollars) is just a myth and nothing more.
How and where information is stored
The database of cryptocurrencies (transactions, balances) is stored as a chain of blocks based on Blockchain technology. Anyone can view information about all transfers. Each new block contains information about previous transfers, commissions and other service information.
New blocks in the blockchain chain appear for each coin with a certain frequency. This interval is known and determined in advance. For example, every 15 seconds (for Ethereum), every 2.5 minutes (for Litecoin), every 10 minutes (for Bitcoin).
Each new block appears as a result of the work of the miners. This work (process) is called "mining".
Miners maintain the network and allow the cryptocurrency to function: make transactions and protect it from hacking. In return, they receive a reward from transaction fees and the production of new coins. We'll talk about this a little lower.
Many people argue about "is it possible to call cryptocurrency money?" This question requires a detailed answer. To be brief: it is really difficult to call it money. Indeed, in our usual understanding, something must stand behind money. In this case, the cost of digital money is determined only by the demand for it. If there is demand, then they rise in price, if there is no demand, they become cheaper. But on the other hand, they can be exchanged for real money.
In 2018, some countries recognized it as a payment instrument (Japan, Germany), but not money. In 2019, some countries allowed to officially pay salaries in Bitcoin. In 2020, Korea fully legalized all operations with crypto money.