AWOL:
When sending angle, the servo does not go to true angle.
The "angle" is simply an abstraction; the Arduino has no idea of the position of the servo.
Neither, come to think of it, does the servo. It merely moves to a position that minimises the error between the measured position and the commanded position.
What is your actual problem?
I want to turn servo to angle I want like 120. What should I change my codes ? When I send 120 angle, the servo send me ASCII characters; 49,50 and then 48 