I struck with the opening word document, PPT by using cordova inappbrowser.
The ideal way to do this is to use plugins like cordova-plugin-file-transfer
to download the file into device and cordova-plugin-file-opener2
to open it using the default app in the device, for a specific file type.
If you really need to open it using a web view or inappbrowser, the best way would be to use external services like google docs. See following example
https://docs.google.com/gview?embedded=true&url=https://www.unm.edu/~unmvclib/powerpoint/pptexamples.ppt