I am new to PowerShell and would like to create a new custom root Folder in Outlook for all existing and new staff going forward. We have a hybrid environment with Exchange Server 2013 and our Office 365 tenancy. I see a script here https://gallery.technet.microsoft.com/office/Create-a-Custom-root-5f32683f but am unclear if this would accomplish the objective. Any assistance would be appreciated.
I have not tested that particular script, but it looks pretty close to one I've used in the past to create custom folders in O365. We did it as part of onboarding users. You will need to change the $FolderName variable along the $user and $pass variables. The script will require you to save your password in the script in plain text, which is generally a no-no, but as I recall, there isn't a much better way of doing it.
If you wanted to give it a try, I say create a shared mailbox and change
$a = get-mailbox
to a single mailbox
$a = get-mailbox "Shared Mailbox"
and give it a try. You'll have to do some more editing if you wanted to import a list of users to the script or find recently created users to create the folders to their mailbox.