I don't know about PPT.

In Word I would do this with an AutoOpen macro that increments either a document variable or a document property. Then I would display that with a document variable or document property field in the footer. The AutoOpen macro would update the field.

This of course assumes that macros are able to run in that document.

If there are a number of documents you do this with, I would consider adding the macro to the DocumentOpen event in a global template.

For me, these are not trivial exercises. I would expect to spend 1-3 hours doing it. I am a dabbler, though, not a programmer. Someone else may be able to present a macro solution.

I would ask why you want to do this. There may be an easier way to accomplish your goals.