Connecting your store to your Facebook page gives you a new channel to reach an audience. Your Facebook friends can see, share, and like your products from their Facebook feeds – as well as go to your site!
Connecting Shopify To Facebook
Go to your Settings / Sales Channels page from the admin panel (quick link)
Click “Add Sales Channels” and choose Facebook from the list by clicking the Add Button
Click “Connect Account” to connect your store to Facebook