You can add lead and client social media accounts from the Contact information section. Here you can add a website, Facebook, Twitter and LinkedIn. When done click on Save.
Once social media added, the social media icons will become available on the lead profile giving you direct access to interact or post directly in their profile with a single click.
IMPORTANT! To be able to interact with your lead via social media you will have to sign up with your own Facebook, Twitter or LinkedIn credentials.