VMWARE

You need to power off as Andy said.
Enabling memory hotplug makes windows to request extra reboot at first startup
Adding CPUs with hotplug (bit not enabling CPU hotplug) will also need extra reboot.
Remember that hotplug CPU option enabled means no vNUMA
i.e power off VM, do all the changes (I advise against CPU hotplug), once machine boots log in as admin, wait for hardware dialogs to finish in reboot popup, and reboot for good now.
Also snapshots cannot be used resizing disk, you have to make a disk clone with Veeam or VM powered off.

after changing the disk size on VMware , should I go to that server and do some changes in disk management

Correct, you will need to use Extend/Expand on the volume.

there are 2 disks showing on VMware, so which one should I expand

the disk which needs to be expanded!

"How would we know, which needs to be expanded"

what sizes are they ?

please find attached 2 virtual disk sizes.

I was told to add 500 disk space.

my question is can I add in any disk?

I was told by my VMware person that disk2 will be ok but I don't know why
C--Users-ic1pxk-Desktop-Capture.JPG
C--Users-ic1pxk-Desktop-Capture2.JPG

should I just extend simple or spanned volume?

Just extend simple.

I added 500gb to a disk on VMware and then went to server and  in disk management and created simple volume on allocated disk space , it created new volume called E.

there was already volume called D which was supposed to get extended but I created new volume  so how can I revert back and extend volume D instead.

also do I need to do anything for paging file which is c drive as I had increased memory from 4gb to 16gb on VMware.

Delete the E: volume you created, and right click D, and select Extend/Expand.

thanks

no problems.