I setup a wiki named Hudu and platform is only on Ubuntu version 18.04.4 LTS. It is a virtual machine that resides in a Hyper-V host. I set the virtual disk to 128GB initially and noticed that because of the attachment of pictures, it rapidly grown bigger and I want to expand the disk. I scheduled it for a shutdown maintenance in order for me tio expand the vhd/virtual disk, add free space, it now has 250GB but correct me if I'm wrong, I turn on the virtual machine I thought it would automatically occupy or add those free space but it didn't. Tried the command 'df' but stil shows the same free space.

How do I add the free space on this?

Thanks in advance