To access LinkedIn information in Outlook 365 desktop subscriptions, you need to enable File > Options > General – at the very bottom, Enable LinkedIn features in my Office applications. Once you do this, you will be able to access LinkedIn information for people in Outlook. Hover, over an address and click the LinkedIn button on the profile card.
LinkedIn integration is available in Outlook on the web (including Outlook.com) and in Outlook 365 subscription. LinkedIn contact support requires an Office 365 mailbox and Office 365 software subscription.
If you don't have a LinkedIn account or are not signed in, you'll have less information than if you are signed into a LinkedIn account.