- Click the File tab, click Open & Export, and select Import/Export.
- Select Import from another program in the Import and Export wizard and click Next
- Select Outlook Data File (.pst) and click Next.
- Browse for the Outlook PST data file, select it and click Next.
- Set Options according to your preference to manage duplicate items in the file and click Next.
- Choose the Import items to the same folder in the option and select the Microsoft 365 mailbox, Click Finish.
Hope This Helps,
Peter