The resources can be grouped into resource groups, which provide logical containers for all related resources. The grouping of resources into resource groups is up to you--you can choose to group them by application, by resource type, by environment, and so on.
Resource groups are also a logical container in terms of Role-Based Access Control (RBAC), which allows you to assign management roles (owner, contributor, reader, and so on) to users or user groups. RBAC roles can also be assigned at subscription or even specific resource levels.
