Functional training exercises are the most customized form of movement available to allow you to improve your daily function.
Your daily function could be holding your toddler in your arm during breast feeding, chasing after your five year old, sitting at your computer for hours, trying to take your t-shirt off without pain, kicking the soccer ball without a twinge in your knee, bending down to lift the grocery from your car without fear of low back injury, lifting the heavy fire hose as a fireman to name a few.
The hallmark of functional training is that it is skill based. There is no biceps workouts, ab workout or lat workout. Many of the motions have no name and all of them have to be customized to your needs.
The customization usually happens by corrective exercise specialists.