One of my 2013 turn signal bulbs died so others will probably be having the same repair. I replaced the bulb myself and can offer some help for others.
The front turn signal bulb type is wrong in my manual. The number on the bulb is 3457NAK. (NA=Natural Amber color, K=Krypton or Long Life)
The days of the simple bulb replacement are over. Ford says to remove the headlight assembly to replace the bulb and that does seem to be a requirement unless you have very long, strong, fingers with some weird joints. Look at the post for removing the headlight assembly to see what is required. You may want to take the car to the dealer and pay $100 to get the bulb replaced.
My bulb was not actually burned out. These bulbs have wire leads and one of them got hot due to poor connection with the socket. The bulb has a plastic base and the hot wire sank into the base until it no longer made contact with the socket. I didn't see any damage to the socket itself. My 2013 Chrysler has the same kind of bulbs and has had the same burned wire problem.
You may notice that the bulb can be plugged in two ways. With the standard bulb, it doesn't matter which way it is plugged in. If you are changing to an LED bulb, it may matter and you will have to see which way the bulb lights. Note that LED bulbs do not use enough current to make the flasher work properly and a resistor has to be added to simulate the original bulb.
Sometimes I wish Ford would just change to all LED lighting but then I would complain when I had to replace a $400 assembly for a failed LED.