Updated: Dec 24, 2019
Microsoft suggest the best practice for mailbox archive is in-place archive when you are using Office 365/Exchange Online/Microsoft 365. This online archive does not require to export emails into PST files, instead, an in-place archive folder appears in Outlook when it's active.
Here are the steps how we achieve:
1. Create Retention Tag
2. Create Retention Policy
3. Assign Retention Policy to particular user mailbox
4. Enable In-Place Archive
5. Wait for 72 hours for effective/Enforce to archive now (PowerShell Command)
The following is the video how you do it.
PowerShell to enforce in-place archive to take place:
Start-ManagedFolderAssistant -Identity “user mailbox”