The Paper Trail missions are free DLC that is available to everyone as part of an update to the game. In order to fully complete these missions, you will need to create an account on inFAMOUS Paper Trail. Once everything has been set up and you've followed the instructions there, play the game until you get the Neon powers.
When you have gotten those, a symbol unlike others in the game will appear at the spot where Fetch first took a shot at you (the billboard). Go there to officially start the Paper Trail missions.
