When you create or edit a farm or a VDI desktop assignment, you have the option of increasing the OS disk size value. When that option is used, the OS disk of each VM in that farm or assignment is created at that size. However, as a result of default behavior of VMs in Microsoft Azure, even though the VM's disk is expanded, the partition containing the C drive is not expanded to encompass the entire disk. That new space on the VM's disk is unused until you take actions in the VM to expand the C drive partition to encompass the new space.
Microsoft provides several ways to expand the partition to cover the full disk. The following Powershell commands are untested by VMware and are given only as an example of one way the expansion might be achieved using a script. You must determine the method that is most appropriate for your organization.
$size = (Get-PartitionSupportedSize -DiskNumber 0 -PartitionNumber 2) Resize-Partition -DiskNumber 0 -PartitionNumber 2 -Size $size.SizeMax
This example assumes the disk number is 0 and partition number is 2. More information about these Powershell commands is available at https://docs.microsoft.com/en-us/powershell/module/storage/resize-partition?view=win10-ps.