anytime I turn the steering wheel I hear a crakling sound.
what causes this
Without having more infromation, there are a few things that I can think of right now that could cause a noise.
Bad power steering pump (check valve or fluid low)
wore out steering rack
wore out CV joints
wore out ball joints
wore out wheel bearings.
wore out stabilizer bushing
and I am sure there are plenty of more reasons. If you need more information directly related to your vehicle, start with telling us what vehicle you have and what noise you hear when.
If the sound is coming from the the steering wheel / column area it could be the SRS clock-spring. This clock-spring provides they connection to your steering wheel air bag and will start to make noise as the car ages.
This is more of an annoyance, but if the clock spring breaks then you will get an SRS light.