Add border to header?

I want to add a border just below my page header, to help achieve a tidy, clearly-defined separation between the header and page contents, however there doesn’t seem to be an option to do this; I can find options to add border to the page margins, but not below the header.
Seems like a fairly simple function; I often see a broken border below the header in many of the books I read. Any idea how to do it?

Follow the pictures … ( Win10 + LibO )

Choose the edge position.

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