I have a script that I use for Archiving and Disabling mailboxes on prem. I would like to know what I would need to change so it can be used in O365 Exchange.
Broadly speaking, you’d need to start by creating a session to O365, and then importing the Exchange cmdlets (Import-PSSession) from there. If you don’t add a prefix to the imported cmdlets, and you don’t have your local Exchange cmdlets imported into your shell, then your script should use the O365 cmdlets.
From there, you’ll need to figure out if your script is doing anything O365 doesn’t allow. Its cmdlets are somewhat stripped down - missing certain parameters, and so on.