You can only export Mac Outlook items as an .olm file, which can seemingly only be imported into Outlook on Mac, or with third-party software if it’s on another app)
On the Tools tab, choose Export.
Note: Don't see the Export button? Make sure you are using the legacy version of Outlook. On the Outlook menu, see if there is a checkmark beside Legacy Outlook. If there isn't, select it and wait for Outlook to restart in Legacy mode.
In the Export to Archive File (.olm) box, check the items you want to export, and choose Continue.
In theSave As box, under Favorites, choose the Downloads folder, and click Save.
Once your data has been exported, you'll get a notification. Choose Finish.