The variables section is used to specify one or more values that will be used throughout the template. A common approach is building the names of all resources in the variables section, based on a single parameter called environmentName. This ensures that resources will have the same name between environments. Variables are also used to specify values that cannot be specified from outside the template, but should be recognized as configurable. An example might look like this:

{
  "appServicePlanType": "B1",
  "appServiceName": "[concat('myAppService-', parameters('environmentName'))]"
}

Please note that the example for appServiceName contains functions that are discussed in detail in a later section called Functions.