These days people have most of their personal contacts in social media accounts like Linkedin and Facebook. The good thing about many Microsoft products these days is that they provide the ability to link to these. This is also the case for Office 365.
If you login into your Office 365 portal and select People from the menu across the top.
In the lower left you’ll find a link Connect to social network. Press this.
You should now see a list of social networks you can connect to. Elsewhere I have seen Facebook also appear in this list but for some reason I am only seeing Linkedin on my tenant.
Press the Connect link.
Allow Microsoft Office 365 access to your Linkedin account.
Then in a manner of minutes all you social network should appear as contact in Office 365.