Graphic design has 3 main things, Concept, Idea, ad life. Graphic design is in everything, from book covers to signs. There is a message to every design and there is also a purpose on why they created it. People use words and images to send a message through the design. Design can pull someone in to buy or read something. Graphic design is very important, if we didn't have graphic designers everything would be blank and boring. It may take a long time to finally get the right design that you think looks good and also send that message. 

 Even the McDonald's logo took lots of time to design.  Designers try to send a message and attract the customers through bright colors.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
                                                                                                                 
http://www.kcai.edu/academics/majors/graphic-design

This talks more about graphic design and the concepts of it.