Can I add a shortcut to a locally stored file? I'd like to add a shortcut on Android 4.2.1 to a local pptx file.

Is that possible ?
In fact it's easy to do using a file explorer application.

I used ES File Explorer but I suspect other programs have the same feature.

Using ES File Explorer, you have to navigate to the file, then do a long click on the file icon until a menu appears. Then you choose Shortcut. Nothing shows the operation works but a new icon will be present in the launcher.