How to deploy app with "pre-installed data"?

Overview:

I have a program that reads XML files and an editor provided with the program. Users can create and share one or more XML.

What I got:
I export my Windows project to VS and do a lot of stuff out there, it’s easy to put all the XML into a folder, which is set to export. The data will be there the first time the user start the application.

The Problem:
I went to an Android version, Unity has some mechanism like that?
I can do thatin Unity, develop an application for Android/Win/IOS with initial XML files?

You could try publishing your XML in assets/ folder and get it through the asset manager.

Though the correct way is probably to use asset bundles and Unity - Scripting API: Application.persistentDataPath. File operations are not really typical and recommended for a mobile platform.