In computer science, the term "cloud" describes a shared resource pool that is made available to several users via the Internet. These resources primarily relate to data storage and computational capacity, but they can also include other services, apps, networks, and servers. The majority of the time, cloud-based resources are simple and convenient to access, offer varying degrees of scalability, and may be dynamically changed to meet various needs. Cloud computing is widely used in many aspects of contemporary life. The development of many services and applications uses cloud computing. For instance, on-demand streaming services like Netflix use cloud computing capabilities to scale efficiently and provide the best possible consumer experience. Well-known voice and text messaging apps like Skype and WhatsApp also leverage cloud computing to facilitate high-quality communication between their users. Other examples are the cloud-based services provided by Microsoft Office 365 and Google G Suite, which are helping millions of people across the world and making it simple to function and engage in real-time from any location at any time. Cloud computing is a technology that consists of three service models and four deployment techniques, according to Peter Mell and Timothy Grance of the US National Institute of Standards and Technology (NIST). The three different kinds of cloud computing services are as follows: Infrastructure as a Service (IaaS): This service provides networking, data processing, and storage as well as basic computing resources. These might be created utilizing cloud computing tools like Google Compute Engine, Microsoft Azure, and Amazon EC2. Users can create, purchase, and deploy user-generated programs on cloud computing platforms using platforms provided by PaaS (Platform as a Service). Among others, PaaS models are employed by AWS Elastic Beanstalk, Heroku, and Google App Engine. Software as a service (SaaS) combines software with cloud-based infrastructure. Users have access to a provider's databases and software, and the cloud provider has complete control over the operating systems and supporting infrastructure that the applications use. Salesforce, Office 365 from Microsoft, and Slack are a few SaaS models. Following are the four cloud deployment models: A public cloud is one that is owned and operated by businesses, governments, or independent cloud service providers. All users are welcome to use public clouds without restriction. A private cloud is one in which the IT infrastructure is virtualized and distributed solely for the benefit of a single company and its customers or business units (i.e., it is not open to the general public). A community cloud is one that virtualizes and distributes IT infrastructure for a particular group or community of users who have similar goals and difficulties (for instance, security standards, legal requirements, and compliance issues). A hybrid cloud is a combination of two or more different (private, public, or communal) cloud infrastructures.