Great question! You can open the gas tank—or rather, the fuel fill door itself—on your Ford C Max by finding the button marked by a gas pump on the left side of your instrument panel and pressing it.
After you press this button, the fuel fill door will automatically open and the fuel tank refueling valve will unlock—just note that it can take up to 15 seconds for the door to open upon pressing the button.
Once you’ve got the fuel fill door open, you’re all set to refuel, as the Ford C Max uses a capless refueling system, which means you won’t have to unscrew a gas cap to start pumping gas—just stick the fuel nozzle into the filler pipe, latch it, and you’re good to go.