Cryptocurrency are digital assets that can stand in for physical, tangible money like US dollars. The virtual currency, which is secured by cryptography, is nearly impossible to double spend or counterfeit.
With the transactions being done on the blockchain, the data is permanently kept in the blockchain’s ledger, and anyone connected with access could see this.
When we make online payments, the principle is similar, though we never see the physical money move, our payments are still made; of course, provided the money is in the account.
In a way, the idea of cryptocurrency can be seen as an evolution of current digital payments.