A resource group allows for us to leverage a logical container to manage our Azure resources in an efficient way.
For example, let’s say this website requires a VM, some storage, and a user database. All of these resources would then be managed under one resource group for efficiency. By using a resource group we could assign access controls for the right users only to the groups they controlled or we could get a breakdown for how much a specific group costs to run or we can push an update to all resources in the group at once or if it a resource group is no longer needed we can simply blow it all away.
To create a resource group, start by opening the Cloud Shell terminal from the Azure Portal.
$resourceGroupName = Read-Host -Prompt "Enter the name of your Resource Group"
$location = Read-Host -Prompt "Enter the location (i.e. centralus)"
New-AzResourceGroup -Name $resourceGroupName -Location $location
Reference:
https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/manage-resources-powershell