Hi Itumeleng Molehane,
Thank you for reaching out to us on the Microsoft Q&A forum.
Yes, it is possible to expand a disk on an Azure virtual machine. Please follow the steps mentioned in the Azure documentation in the given link- https://learn.microsoft.com/en-us/azure/virtual-machines/windows/expand-disks
If you observe below issue during expansion of OS disk, deallocate particular VM and resize the OS disk.
If you have any additional questions, feel free to reach out. If the information provided above was helpful, kindly accept the answer as a token of appreciation.