Cloud computing enables companies to consume a compute resource, such as a virtual machine, storage, or an application, as a utility -- just like electricity -- rather than building and maintaining computing infrastructure in-house.
The following attributes can characterize the cloud
The Cloud Provider provides these shared resources.
See also Cloud Service Models - snippset
Companies use different cloud environments for legacy reasons or leverage the right cloud service based on specific needs or requirements like data sovereignty or other regulation.
Reasons for a hybrid and multi-cloud strategy