Golden Rule: do not confuse "Headings" with "Page Headers" and "Page Footers".

"Headings" appear within the actual body of a document, such as the Title of the topic on this page.

A "Header" or "Footer" is what appears consistently at the top and bottom of a page (inkprint or braille).

The codes and parameters explained in the centering topics here are employed in the h1. style. Once you have understood the workings of these codes, if you wish, you can create custom heading styles of your own.