Explanation:
Box 1: A policy
Control costs by limiting the number of high-cost resources that can be provisioned in the subscriptions.
Use Azure Policy to set policies such as restricting the creation of high-cost resources in some subscriptions.
Box 2: A tag
Group all the resources by application for cost reporting.
To group multi-subscription Azure costs by application, the best approach is to consistently apply Azure Tags (e.g., ApplicationName, Environment) to all resources, then use Azure Cost Management's Cost Analysis feature at the Management Group or Billing Account scope to filter and group by these tags, revealing application-specific costs across subscriptions in a unified view. Alternatively, use Cost Allocation Rules for dynamic grouping or third-party tools for advanced analysis.
Box 3: A management group
Control costs by monitoring resource usage.
A management group in Azure is crucial for controlling costs across multiple subscriptions by providing a scope to apply governance, monitor usage centrally via Cost Management, and enforce policies, allowing for aggregated views and better optimization than managing each subscription individually. You can see costs rollup from nested subscriptions, track spending trends, and identify resource waste at the management group level for better financial control.
Reference:
https://techcommunity.microsoft.com/discussions/azure/a-complete-guide-to-azure-cost-management/4386446
https://learn.microsoft.com/en-us/answers/questions/1663822/cost-analysis-and-optimization-across-multiple-sub