i want to open sorce code and database how we have to open it.
What exactly do you want to open source? An extension?
i want to open my erp next source file
did you make a custom app which you would like to Open Source (I’m not really understanding you, sorry)? The erpnext core is open source already.
if we want to do any change i source file
how can we do
To change the internals is bad idea. But if you want to, there’s not much you need to do: just fork the repository, and checkout your fork.