Some of the prominent advantages of IaC is that it can be version-controlled. It can be reused across environments, which provides a high degree of consistency and predictability in deployments. It also ensures that the impact and result of deploying an ARM template is the same no matter the number of times the template is deployed. This feature is known as idempotent template.
ARM templates debuted with the introduction of the ARM specification and have been getting richer in features and more mature since then. It's important to understand that there's generally a feature gap of a few weeks to a couple of months between the actual resource configuration and the availability of this configuration in ARM templates.
The resource has its own configuration. This configuration can be affected in a multitude of ways, including using Azure PowerShell, Azure...
