File System

I am assuming that you want to open an existing app that is already installed on the device rather than handle the editing yourself within your app.

You will need to use intents and mime types to get the device to display the available applications that can read the type of file (you could set one explicitly if you know it will be installed.)

B4A Intents

B4A Wiki documentation for intents

List of Mime Types

Thanks for your reply.but i want some example code to open pdf or jpg file using intent.

You can find some code samples HERE