Open the harmon.ie add-in:
In the Outlook client, click the Add from SharePoint icon () in the harmon.ie ribbon-button.
In the Outlook Web app, click Add-ins > harmon.ie.
In Outlook mobile app, tap the Actions menu > Add-ins > harmon.ie.
If prompted to Connect to Office 365, click Connect and follow the on-screen instructions.
Select the SharePoint location from which you want to add documents:
Recent: lets you view locations you recently uploaded to, and files you recently worked with in Office 365. From here you can quickly access SharePoint documents.
Sites: lets you browse to a document library/folder/document set and view its documents.
Teams: lets you connect and browse through your Office 365 Teams documents.
Sites I'm Following: lets you connect and browse to a location in a site you follow in SharePoint.
Pinned: lets you view a location you previously pinned.
Click the More icon () next to the document you want to add, and select:
Add as Link () to add a link to the document. This option is available when composing an email.
Add as Attachment () to add the document to the email. This option is available when composing an email.
Compose Email with Link () to create a new email with a link to the document. This option is available when reading an email.
Reply with Link () to reply to the selected email with a link to the document. This option is available when reading an email.
The icon indicates that the document was added to the message ().
You can also select Open in Browser/Word/Excel/PowerPoint or Open in Word/Excel/PowerPoint Online to open and work with any SharePoint document.