but my question is i suppose that it's need to use Adafruit_PWMServoDriver.h to work?
Yes, the library is needed to send commands to the board.
Is the command pwm.setPWMFreq (60) is need for led control? What is exactly the function of this command.
setPWMFreq controls the PWM frequency. 60Hz is a good frequency for controlling Servos. It will work for LEDs too, but you might see a bit of flicker at that rate. Setting it to a higher speed like 1000Hz would be better for LEDs.