Cryptocurrencies are a method opposite to conventional currencies that are centralized and organized by entities and Banks (Pesos, Soles, Euros, Dollars, etc). 
They are, therefore, a decentralized alternative to fiat currency (issued by a government, legal tender). They are also often called "cryptocurrencies" or "crypto assets." 
They are then a digital medium of exchange, which uses cryptographic methods to secure its financial transactions, controlling the creation of new units and verifying the transfer of assets.
They are digital money. The money of the future.
The cryptocurrency market is based on speculation, so it carries a risk, involved in supply and demand. Collections and payments are made through cryptography, which protects users, so they do not need the control of any institutional entity. Being decentralized, it is not necessary to reveal any private data of your identity, nor is it required an intermediary to negotiate. The transactions are irreversible. There is no possibility of forgery or duplication.
You can't talk about cryptocurrencies without talking about BLOCKCHAIN.
The decentralized transaction system is known as BLOCKCHAIN (chain of blocks). Since each transaction is called a BLOCK, which has a UNIQUE AND UNREPEATABLE code that stores data, both from the sender and the receiver through codes.
For each operation a block is generated, which is registered by a network of users who can see said transaction. This block is joined to other blocks as a CHAIN, linked to each other, where all the operations of the cryptocurrency in question are recorded, from its starting point, until it reaches its recipient and leaves again in the future at Other users.
In turn, this chain is viewed by millions of users from their screens, as a duplicate of the transaction, on billions of screens around the world. With so many witnesses evidencing the transaction it is practically impossible to commit fraud, since there are millions of witnesses who have registered the operation.
Where to buy cryptocurrencies?
Coinbase:
https://www.coinbase.com/join/cardoz_dr
Coinswitch
https://coinswitch.co/?ref=RG3GG016AW
QubitBrokers
www.qubit.com.ar/accounts/register/?ref_user=3U44WXT
Crypto.com
https://platinum.crypto.com/r/pkrcvzhnw5
