When someone shares on facebook, it will look like the picture below. you can cutomize everything using the fields on the right.
                 
                  
                  
                  
                  
                
               
                  Click the button below to customize the social network sections
                  
                 
                
   
                  
                  
                 
              
              
             
           
       
     
    
      
All of these settings can be later changed from your admin control panel.