Nokia Lumia 800 - What kinds of files can my Nokia Lumia open in Microsoft Office Mobile?

The following file types are supported:

Word Mobile:  .doc, .docx, .dot, .dotx, .dotm, .docm .txt, .rtf Excel Mobile:  .xls, .xlsx, .xlt, .xltx, .xlsm, .xltm PowerPoint Mobile:  .ppt, .pptx, .pps, .ppsx, .pptm, .ppsm OneNote Mobile:  .one

Office Mobile lets you create, edit and share office documents on the phone. You might not be able to edit a certain documents depending on what is in it or how it was last saved. For more information, go to the www.windowsphone.com, then search for the How-To article: Why can't I edit some Microsoft Office documents on my phone?