I was lately adding some help content to the create/edit form pages of an internal (dev team) change manager application. This is how i did it, discussing some aspects of the design approach as well as the actual execution with apex 3.x (I’m still with apex 3.2, since this version is quite sufficient for an internal app).
Providing on page help for form pages is usually a game like this: some input field may be called “Creation date” and the help text goes as “This is the creation date”. Wow, this is what the world needs to know! I more or less get angry or better ignorant seeing this information garbage but that’s another story. I prefer on page help content that provides page context information, just pointing out dedicated input fields only when necessary.
In fact, apex puts both approaches at your disposal. The key element with apex is the help text region that you may add with the create region dialogue on a page.