I have a DA IC(AD5668) whose output is 0-5V. I
want to transmit the singal with diferential (-10V to +10V)
how would I go about converting the signal
from one format to another.
It's called converting an unipolar signal to a bipolar signal, and this place has a design example & guide.
You'll either need different reference voltage & resistor(s), or another amplifier with a gain of two after that converter, to get +/- 10V.