I had over 100 VMs to add descriptions or notes and then Move them to a folder so decided to write a one-liner for it. Hope it comes handy for someone looking to do similar task.
Import-Module vmware.vimautomation.core
#Get-Module -ListAvailable VMware* | Import-Module | Out-Null
Connect-VIServer uk3p-vc01.lab.local
Import-Csv "C:\scripts\VMNotes.csv" | % { Set-VM $_.VMName -Description $_.Notes -Confirm:$false}
## Now watch the magic happens
Create a CSV similar to below
Connect to vCenter with enough privileges to add notes or description to existing VMs
Import-Module vmware.vimautomation.core
#Get-Module -ListAvailable VMware* | Import-Module | Out-Null
Connect-VIServer uk3p-vc01.lab.local
Import-Csv "C:\scripts\VMNotes.csv" | % { Set-VM $_.VMName -Description $_.Notes -Confirm:$false}
## Now watch the magic happens
