Introduction
Folders in an Outlook mailbox may be shared with one or more people. This useful when a colleague needs to see emails which have been sorted manually or automatically (by an inbox rule) to a specific folder.
Instructions
Share a folder
In Outlook on the web, a folder may be shared by right-clicking on an inbox folder, and choosing the Sharing and Permissions menu item.
From the popup that displays, add the person and then appropriate permission level.
Read about the activities (abilities) a sharing user can perform here: Options for sharing a folder
Set the Inbox folder as visible
The Folder visible permission is needed to allow people to traverse the folder hierarchy. Grant the Folder visible permission to the "Inbox" folder so that any child shared folders are made accessible.
For the "Inbox" folder:
Add a Shared folder
In Outlook on the web, right-click on the "Folders" navigation section, and choose Add a shared folder or mailbox.
Enter the person's email address who has shared a folder with you, then click Add.
The person's name and shared folders should appear between the "Folders" and "Groups" navigation section in Outlook.