Microsoft has just released an iPad version of Word, Excel and PowerPoint. For the first time you can now edit Word documents using Microsoft software on your iPad. In the past, there have been third-party applications that will allow you to edit your Word documents. These third-party apps have not always worked consistently. Now at last you can use Microsoft software to edit your Word documents.
The major challenge I see at the moment with this new Microsoft software is that you must have an Office 365 subscription in order to access online documents. Typical Microsoft, they have decided not to integrate Dropbox into these applications, instead forcing you to use their own online system called SkyDrive. I think this is a huge mistake. Many other developers are integrating Dropbox into their applications.