Best Exercises For Triceps 

Triceps have 3 heads and you have to train that Three heads to grow triceps 

1:Lateral Head

The lateral head arises from the posterior surface of the body of the humerus, between the insertion of the Teres minor and the upper part of the groove for the radial nerve, and from the lateral border of the humerus and the lateral intermuscular septum; the fibers from this origin converge toward the tendon.
this is the short head head of tricep and mostly visible from front side your arm and best exercises would be robe pushdown, pully pushdown, dumbbell kick back 

Triceps Exercise

2:Long Head

Long head—The origin of the long head is the infra-glenoid tubercle of the scapula. Because it attaches to the scapula, the long head not only extends the elbow but will also have a small action on the glenohumeral or shoulder joint.
This is the long part of your tricep it helps to create mass in your tricep by traning this you can have huge arms and the best exercises would be skull crusher, overhead triceps extentions  and other overhead exercises
Triceps Exercise

3:Middle Head:

Medial head—The origin of the medial head is at the dorsal humerus, inferior to the radial groove and connecting to the intermuscular septum. The medial head does not attach to the scapula and therefore has no action on the glenohumeral joint, whether with stabilization or movement.'
you dont need to train this seperatly this muscle would automaticly train with ohter exercises 

Triceps Exercise