1. Open Microsoft Outlook and click on File on the top left corner of Outlook.
2. Click on Open & Export.
3. Click on Import/Export from the source
4. Select Import from another program or file and then click
5. Select Outlook Data File (.pst) and click Next
6. Select the Browse option to navigate to your Outlook data file(s).
7. Select the Outlook Data File to import and click Open
8. Click Next.
9. Select Import items into the same folder in: and select your Exchange Online Archive from the drop down
10. Select Import items into the same folder in: and select your Exchange Online Archive from the drop down