Wikipedia defines the Cloud as “a type of Internet-based computing that provides shared computer processing resources and data to computers and other devices on demand.” The cloud gives people a central location where they can house almost anything they need, may it be backups, websites, databases, computing, etc. The use cases are endless. It is designed in such a way that companies can offer up on-demand, scalable, and high performance instances in seconds. Just for reference a couple of the companies that offer such services are Amazon Web Services, Google Cloud Platform, and Digital Ocean.
Amazon Web Services offers on-demand cloud computing platforms. AWS is currently the largest cloud providey in the world. They even have one of the largest marketplaces of custom images that users can load up in seconds.