Different page in website

Hi, I am designing my friends website, a consultancy in wordpress and want to give a different look in different page. Header and footer will be same, But the middle section will be having different arrangement of content in different page. Is this possible. I have tried to make it but only two option is available of index page and blog. Can i add some more pages of my own.

Next i also want to ask can i create a plug-in of my own please guide.

Thanks in advance.