Block-level items automatically start on a new line (headings, paragraphs, and divs) while inline items sit within surrounding content (images or spans).
The default layout of elements in this way is called the normal flow of a document.
Can be overridden.
Final Code
<style>h2{position:relative;top:15px}</style><body><h1>On Being Well-Positioned</h1><h2>Move me!</h2><p>I still think the h2 is where it normally sits.</p></body>