You can specify links to your profiles in social networks and your RSS-feed in Appearance > Customize > Social Media section. The corresponding icons will appear on your site.
The full list of social media supported: Facebook, Twitter, Pinterest, YouTube, Google+, Linkedin, Github, Vkontakte, Instagram. Also E-mail, RSS and Skype icons are available.
For social sharing you may install any plugin you like, for example Social Likes.
Make sure you’ve set Meta Descriptions for your posts for proper excerpts when share on Facebook (if you use Yoast Seo Plugin, put %%excerpt%% in Titles & Metas > Post Types section).