All BlackBerry devices that are running OS 4.3 or lower have the built-in ability to view MS Office files. If you wish to edit these files then you will need to purchase aftermarket software with editing capabilities.
Applications to Edit and Save MS Office Files
Applications to View MS Office and .PDF Files
OS 4.5 and Beyond
All BlackBerry devices with OS 4.5 come standard with the Standard Edition of Documents to Go, giving users the ability to receive, view, save, and send MS Office files.