"Header text" refers to the title or heading at the top of a document, webpage, or section. It is usually larger and bolder than other text, helping to summarize or introduce the content below it. Full definition
Not all templates will display header text on Echo Spot, such as BodyTemplate2 or ListTemplate2. (developer.amazon.com)
Caller said it's far more important that the writer is consistent in terms of layout and style, that she has chosen appropriately professional fonts and borders, and that she delineates header text by position and purpose. (theladders.com)