Hi,
I build a web site in flex that some time take input. Will this website works on Touch Screen environment(KIOSK).My question is we have to make any change to handle input such as prompt on screen keyboard when input fields are get focused or it will manage my device and OS of system(KIOSK, Touch screen system) itself.
I'm unclear exactly what your question is. But, yes, Flex should work on touch screens and traditional screens with a mouse and keyboard.
It is likely that you'll need project modifications for each environment. The size of a button to accept a mouse click is going to be much smaller than what you need to accept a finger click, for example.
You can use a library project to share code between these two projects / interfaces.
I remember using Flex applications on touch screen monitors running Windows/Linux. These operating systems treat/converts touches as/into mouse actions and hence Flex apps doesn't know the difference.
Whether you'll be able to run it on a kiosk depends on the underlying OS. If the OS converts touches to mouse movements, then yeah, your app will run seamlessly.