To be able to host a running applications on the cloud, we have many options.
Our first option is IaaS - Infrastructure as a Service -, where by, the cloud provider takes care of the network access, IP addresses and DNS configuration.
We create our virtual machines on the provider's hypervisor, then, we can install our applications on them.
Our second option would be PaaS - Platform as a Service - which makes it possible for us to run our applications as containers, which are "mini virtual machines" that run on top of an operating system.
Each container is an isolated entity with its own resources and IP address.
SaaS is our third option - Software as a Service -. The cloud provider manages everything from network to hardware to OS. We run our applications on a ready-to use solution: