Hi all thanks for help (in advance)
I developed an HTML form, which takes source and destination from the user and uses python in background to combine those files. I hosted this in my web server but if a user is entering the path which is in his desktop my application is not reading. It is searching for the path in the webserver but not in the user desktop.
You need to provide a way for the client to send the file to the server. The app is running on your web server which has its own file system. This server will not have direct access to clients' file system (this would be a huge security concern).
Sounds like you are trying to develop this as if it is a local app on the client's machine. This is not the case because you deployed part of the app to your web server. Think of your app as two pieces. Server side application / client side application. You need to create a way for these two to communicate with each other in a secure manner.
What you are looking for can be done with a REST endpoint on the server side where a client can send the file to the server via a POST request.
Basically the client side of the app (your webpage) could prompt the client to select a file on their machine and then send the contents of the file(s) via HTTP POST to the server side of your app where your python code performs whatever operations you want. The server app could even send a response back to client (the combined files maybe).
Something like this is what you ultimately need to do... note that in this link they developed BOTH server/client parts of their app in python. In your case you have created a webpage client frontend that will run in a browser. You would need to add some code to your webpage to have the user upload a file from their machine and send it to the server.
Sending files between client - server through TCP socket in python?