Add CPU memory to an existing ESXi Virtual Machine via Powercli

At the Powercli cmd prompt type the following:

Connect-VIserver  Servername

Locate the VM that you want to modified using:Get-VM

 

then use the following syntax

 get-vm ServerName | set-vm -MemoryGB 4096 -NumCpu 2 -Notes "H/W modified $(Get-Date)" -confirm:$false

commands:
Get-VM
Set-VM 
parameters:
MemoryMB = Specify the memory size in megabytes (MB
NumCpu     = Specify the number of virtual CPUs.
Notes          =  Provide a description of the virtual machine. The alias of this parameter is Description

Reference:
https://www.vmware.com/support/developer/PowerCLI/PowerCLI51/html/Set-VM.html