Are there any scale on the touch inputs? I know there is sensibility settings to say if you touch or not, but does it has a scale for hard pressure and low pressure too?
If so, what scale is it? 0 to 1 or 0-255 or what possiblities?
Well, that entirely depends on the API. Android, for example, has a getPressure() accessor in MotionEvents that returns a float between 0.0f and 1.0f, but the actual granularity of your result obviously depends on the hardware - if the screen can only detect "pressed" vs "non-pressed", you will only ever get 0.0f or 1.0f.
EDIT: As per Julio Gorgé's answer, iOS does not offer this functionality.