Bitcoin Cash (BCH) is a hard fork of the original Bitcoin (BTC) currency. Its main goal was to escalate the number of transactions which can be processed by the network and this goal was accomplished by increasing the size of blocks from 1 MB to 8 MB.
BCH currency is used for performing decentralized electronic transactions and Bitcoin Cash also represents a payment processing platform. On the other hand, as we see today, BTC currency is used more like a value storage (a.k.a digital gold).
Bitcoin Cash offers to its users instant transaction speed for minimal fees. This system can be perceived as a competitor to PayPal and Visa.