how to resize your OS disk of your Azure VM to maximum allowed size

1. Run the following PowerShell. Modify the parameters accordingly.

 $cred = Get-Credential
Login-AzureRmAccount -Credential $cred

$resourceGroup = "nerg1"
$location = "North Europe"
$vmName = "nerg1win1"

$vm = Get-AzureRmVM -ResourceGroupName $resourceGroup -Name $vmName 
Stop-AzureRmVM -ResourceGroupName $resourceGroup -Name $vmName -Force
$vm.StorageProfile.OsDisk.DiskSizeGB = 1023
Update-AzureRmVM -ResourceGroupName $resourceGroup -VM $vm
 
Start-AzureRmVM -ResourceGroupName $resourceGroup -Name $vmName

2. Extend the OS disk volume using Disk Manager of Windows operating system.