Browse to a location on your server or in the cloud. If you are using the list view mode, any Word, Powerpoint, Excel or PDF documents will have an additional icon that will bring up the Share menu.
If you are not using list view, simply tap the document to preview it and in the top right corner you will see the new share button.
Now iOS will show you the apps that this file can be passed to. Scroll the list until you find Word.
To speed this up for next time, tap and hold the Word icon to move it to the start of the list.
Word, Excel or Powerpoint will then open.
Simply make your changes and when finished, tap the back arrow. This will save your changes back to the Server or Cloud where you opened the document.
If you don't see the Word, Excel or Powerpoint App Icons appear in the file listing, you need to install the apps which you can do so from here:
Download Microsoft Word here
Download Microsoft PowerPoint here
Download Microsoft Excel here
Download PDF Viewer Pro by PSPDKit here
Download Adobe Acrobat here