In any text, there are two sorts of headers: main headings and subheadings. Main headings are the first words on a new page or line. They give readers an idea of what will follow and they often serve as titles for paragraphs or sections. Subheadings are subordinate headings; they can be used to divide up any section of text, including chapters and articles.
Subheadings should not be considered lower-level divisions within a paragraph or section. Rather, they are independent sentences that usually contain shorter versions of the information contained in the corresponding paragraph or section. For example, if a paragraph's subject changes, then the writer can simply insert a new sentence with a new heading rather than rewriting the entire paragraph.
There are three types of subheadings: major, minor, and catch-all.
Major subheadings are the most important ones and usually take the form of titles for chapters, sections, or subsections. These should be clear and specific enough to provide guidance to readers regarding how much information is contained in the surrounding text.
Headings and subheadings structure text to help readers navigate. A header or subheading appears at the top of a page or section and explains the information that follows succinctly. Do not use full capital letters in headers, such as "THIS IS A HEADING." Use lowercase letters only. Headings should be concise and to the point.
Subheadings further divide the material within the main heading. For example, if the article has a main heading of "How Google Works" with several subsections under it (such as "The Four Types of Google Pages"), then each subsection would have its own subheading (such as "Organic Search").
Subheads should be concise and to the point too.
The primary concepts and supporting ideas in the work are represented by headings and subheadings. They graphically express important levels. Differences in text format assist readers in distinguishing the essential points from the remainder of the text. Headings are usually larger, if not more visible, than subheadings.
The main categories of headings are as follows:
Title (or Subject) - gives a general indication of what will follow. Can be as short as one word or as long as several pages.
Subtitle - provides further detail about the topic covered by the title page. Usually no longer than one page.
Keywords/Matching Words - used to search for information on the Internet.
Abstract - an overview of the subject for those who want to know more about it.
Chapters - groups of related topics covered in one section of the book.
Articles - brief descriptions of studies or research projects.
Periods - shows how recent or old an article is.
Publications - lists works written by the same author or group of authors.
Works - includes editors' notes, bibliographies, index, etc.
Headings and subheadings are used to assist the reader in identifying the primary topic of the entire text (header) and portions of the text (subheadings). They help the reader anticipate what the material will be about. They also provide cues about how much detail should be provided for each subject.
When reading a book on history, it can be helpful to think of the main header as something like "Here is everything you need to know about the Middle Ages." And the subheadings as topics that could appear within this header: "Europe before Columbus, Charlemagne, and Henry VIII."
Without these labels, you might read the whole book without any ideas of where to start or finish. The headers and subheadings make it easier for your brain to process what it is reading. You will be more likely to remember important information if you can group it by subject matter instead of trying to read it all at once.
Books with great headers and subheadings are easier to read and understand. These books are called "helpful readers" because they offer guidance to the reader on how to best use the content.
The goal of a writer when creating heads and subheads is to be as clear and concise as possible while still covering everything necessary for the reader to understand the topic.