Management groups paly a vital role when we want to organise and manage access, polices and compliance across multiple subscriptions.
Management groups are containers with which you can organise and manage multiple subscriptions. Management groups provide a governance scope above subscriptions, enabling you to apply policies and access controls across all subscriptions within a management group.
With hierarchical structure (up to six levels of depth) of management groups, you can recreate your organisation's structure, such as departments or business units. Which makes it possible for subscriptions to inherit policies and permissions from the management group they belong to.
Configuration
You need Global Admin Roles to create the first management group in Entra ID tenant. Azure automatically creates a "Root" management group (at the top hierarchy) that contains all other management groups and subscriptions by default.
Steps:
When you are done creating a management group, you can associate subscriptions with it, apply policies and assign roles at the management group level.
With management groups, you can apply policies, compliance rules and security controls across multiple subscriptions. Consistent RBAC policies can be enforced across your Azure environment, ensuring that all subscriptions adhere to the same access controls.

Ireland | Bobby Abuchi