Crypto or cryptocurrency is a next-generation digital currency. You can use it just like electronic or ‘physical’ money, for example to shop at online and local shops or to pay for services.
Some of the most well-known cryptocurrencies are Bitcoin, Bitcoin Cash, Ether, various tokens, etc. They differ in a variety of ways, but paying with them, buying/selling them or sending them to your friends is exactly the same when you use Elly.