Normal crypto-coins are a digital asset created to work as a medium of trade. Additional crypto-coins may be created via mining. Everyone can do this if they've access to a device. Mining requires a large amount of hours and electrical energy, though. A high-powered computer is also required, to do this profitably. Conversely, XRP is a centralised asset, which can't be mined. A finite amount of units were created by the company and this limit will never be added to.