how to export files into word doc

This is not an out of the box AEM feature. However - you can build a custom AEM service to do this. We have a community article that shows this use case for working with an Excel spreadsheet:

http://helpx.adobe.com/experience-manager/using/creating-custom-excel-service-experience.html

To build a custom AEM service that works with Word - you need to get a Java API that works with MS DOC files. I suggest looking at:

http://poi.apache.org/