This question concerns 'inform on' also, and so doesn't duplicate inform about vs inform of (where user 'Maulik V' asserts the following that I edited):
Inform her of X = Here, we are informing her that X happened. And that is all!
On the other hand, Inform her about X
= Not only will she be informed that X happened, but also the details of X.
Yet how does inform on change all this? What of 'Inform her on X?
I already know, and so ask not, about the following ODO's definition 1.1:
inform on = 1.1. [no object] Give incriminating information about someone to ... authority