Cloud computing companies offer information technology as a service that you can access through the internet. They host and maintain the physical infrastructure required to provide the service, sparing you from capital expenditures and IT maintenance headaches.
Cloud vendors afford you a substantial degree of self-service control over your usage of the cloud service, typically through a web portal and sometimes also through an application programming interface (API).

Cloud computing companies enable you to rapidly scale up or down your service usage. Behind the scenes they leverage virtualization, automation, and other cloud management technologies to facilitate this service agility.
Cloud providers charge you based on how much of the service you use

Cost effective: While traditional IT requires you to purchase computing capacity in anticipation of growth or surges in traffic — capacity that sits unused until you grow or traffic surges — cloud computing enables you to pay for only the capacity you need, when you need it. Cloud also eliminates the ongoing expense of purchasing, housing, maintaining and managing infrastructure on premises.

Improved agility: On the cloud you can provision and deploy  (“spin up”)  a server in minutes; purchasing and deploying the same server on premises might take weeks or months.

Scalability and elasticity: Cloud computing lets you scale workloads automatically — up or down — in response to business growth or surges in traffic. And working with a cloud provider that has data centers spread around the world enables you to scale up or down globally on demand, without sacrificing performance.

Reliability and business continuity: Because most cloud providers have redundancy built into their global networks, data backup and disaster recovery are typically much easier and less expensive to implement effectively in the cloud than on premises. Providers who offer packaged disaster recovery solutions— referred to disaster recovery as a service, or DRaaS — make the process even easier, more affordable and less disruptive.Improving performance. The leading cloud service providers regularly update their infrastructure with the latest, highest-performing computing, storage and networking hardware.

Better security, built: Traditionally, security concerns have been the leading obstacle for organizations considering cloud adoption. But in response to demand, the security offered by cloud service providers is steadily outstripping on-premises solutions. With the right provider, cloud also offers the added benefit of greater choice and flexibility. Specifically, a cloud provider that supports open standards and a hybrid multicloud implementation (see “Multicloud and Hybrid Multicloud” below) gives you the choice and flexibility to combine cloud and on-premises resources from unlimited vendors into a single, optimized, seamlessly integrated infrastructure you can manage from a single point of control — an infrastructure in which each workload runs in the best possible location based on its specific performance, security, regulatory compliance and cost requirements.