The evolution of the cloud technologies has took the internet services to a whole new domain. Primarily Cloud technology was mainly used for storage purpose, but now with Service Workers making its way into the mainstream media. All of a sudden cloud is used for caching, setting up virtual machines and for responsive designing.
While testing it is not feasible to set up infrastructure and physically install the various OS on them. By the use of cloud you can set up the desired machine with distinct specialization. There are a lot of companies which can offer you cloud infrastructure, but if your end goal is testing then I suggest you give LambdaTest a chance. It is a wonderful tool that helps you achieve cross browser compatibility for your website or web app.