What is Azure Service Bus? HCL Interview

Azure Service Bus is an asynchronous messaging cloud platform that enables you to send data between decoupled systems. Microsoft offers this feature as a service, which means that you do not need to host any of your own hardware in order to use it.
Service Bus is a multi-tenant cloud service, which means that the service is shared by multiple users. Each user, such as an application developer, creates a namespace, then defines the communication mechanisms she needs within that namespace.
See below image it shows how this looks.