Sectioning commands provide the means to structure your text into units.
\part
\chapter
(report and book class only)
\section
\subsection
\subsubsection
\paragraph
\subparagraph
All sectioning commands take the same general form, i.e.,
\chapter[optional]{title}
In addition to providing the heading in the text, the mandatory argument of the sectioning command can appear in two other places:
You may not want the same thing to appear in these other two places as
appears in the text heading. To handle this situation, the sectioning
commands have an optional
argument that provides the text for
these other two purposes.
All sectioning commands have *
-forms that print a title,
but do not include a number and do not make an entry in the table of
contents.