Include logo on the header of all the pages.
In that sentence, is it correct to use on or should it be in?
I have a decent idea of where to use on and in most of the time. But in the above sentence, both seem to be correct.
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It only takes a minute to sign up.Sign up to join this community
"In the header" sounds a little better to me.
When it comes to text and graphical elements in a document, there seems to be a subtle difference between "in" and "on." "On" is more literal and specific. It makes me think of something actually being on the surface of the page. "In," on the other hand, seems to be slightly more abstract, and is applicable to more cases.
I suppose it depends on how you think of a header. Is it an abstract, conceptual unit like a paragraph? Or is it a part of the physical page? I think it is more like a paragraph, especially from the point of view of the person creating the document.