This option allows you to share your entire Contacts folder for other users to view. You are unable to see any contacts that are shared with you in the online version of Outlook available through Office 365.
Note: You can only share contacts through the desktop/client version of Outlook. This article will review the different ways you can share your contacts or contact list in the desktop/client version of Outlook. Sharing Contacts or a Contact List in Outlook (Email)
