New-RetentionPolicyTag "ArchiveTag" –Type All –RetentionEnabled $true –AgeLimitForRetention 90 –RetentionAction MoveToArchive
New-RetentionPolicy "CorpPolicy" –RetentionPolicyTagLinks "ArchiveTag"
Set-Mailbox <mailbox> -RetentionPolicy "CorpPolicy"
Start-ManagedFolderAssistant –Identity <mailbox>
However, after you create the retention policy, the policy doesn't automatically run. That is, messages that have reached the age limit that's set in the policy aren't automatically moved to the user's archive mailbox.
Article ID: 2627729 - Last Review: Dec 16, 2016 - Revision: 1