To use or see the social sync option you will first need to go to the people tab.
The system will automatically search for their social media that is tied with their email or phone number that they provide. If they do not have any social media linked like Facebook then it will let you know in their profile like below.
However, If they have social media that is tied to their info then the system will notify you and you can sync it up with their profile.
Once you click on the Add Social Data option that is in blue, it will bring in their info and even a profile picture from Facebook!
This will be a great help in placing a face to the name of a person as well as other great info. This will also be displayed in their profile as well!