Documents that are small and static can have a manually produced index. This will make a separate page labeled ‘Index’, in twocolumn format.
\begin{theindex}
\item acorn squash, 1
\subitem maple baked, 2
\indexspace
\item bacon, 3
\subitem maple baked, 4
\end{theindex}
Note that the author must enter the page numbers, which is tedious and
which will result in wrong numbers if the document changes. This is why
in most cases automated methods such as makeindex are best.
See Indexes.
However we cover the commands for completeness, and because the
automated methods are based on these commands. There are three levels
of entries. As the example shows, a main entry uses \item,
subentries use \subitem, and the lowest level uses
\subsubitem. Blank lines between entries have no effect. The
example above includes \indexspace to produce vertical space in
the output that some index styles use before the first entry starting
with a new letter.