Document classes
The document’s overall class is defined with this command, which is normally the first command in a LaTeX source file.

\documentclass[options]{class}

The following document class names are built into LaTeX. (Many other document classes are available as separate packages; see Overview.)
article 	For a journal article, a presentation, and miscellaneous general use.
book 	Full-length books, including chapters and possibly including front matter, such as a preface, and back matter, such as an appendix (see Front/back matter).
letter 	Mail, optionally including mailing labels (see Letters).
report 	For documents of length between an article and a book, such as technical reports or theses, which may contain several chapters.
slides 	For slide presentations—rarely used today. In its place the beamer package is perhaps the most prevalent (see beamer template).
Standard options are described in the next section.

Document class options
You can specify so-called global options or class options to the \documentclass command by enclosing them in square brackets. To specify more than one option, separate them with a comma, as in:

\documentclass[option1,option2,...]{class}

Here is the list of the standard class options.
All of the standard classes except slides accept the following options for selecting the typeface size (default is 10pt):

10pt  11pt  12pt

All of the standard classes accept these options for selecting the paper size (these show height by width):
a4paper 	210 by 297 mm (about 8.25 by 11.75 inches)
b5paper 	176 by 250 mm (about 7 by 9.875 inches)
executivepaper 	7.25 by 10.5 inches
legalpaper 	8.5 by 14 inches
letterpaper 	8.5 by 11 inches (the default)
When using one of the engines pdfLaTeX, LuaLaTeX, or XeLaTeX (see TeX engines), options other than letterpaper set the print area but you must also set the physical paper size. One way to do that is to put \pdfpagewidth=\paperwidth and \pdfpageheight=\paperheight in your document’s preamble. The geometry package provides flexible ways of setting the print area and physical page size.
Miscellaneous other options:
draft 	final 	 Mark (draft) or do not mark (final) overfull boxes with a black box in the margin; default is final.
fleqn 	 Put displayed formulas flush left; default is centered.
landscape 	 Selects landscape format; default is portrait.
leqno 	 Put equation numbers on the left side of equations; default is the right side.
openbib 	 Use “open” bibliography format.
titlepage 	notitlepage 	 Specifies whether the title page is separate; default depends on the class.
The following options are not available with the slides class.
onecolumn 	twocolumn 	Typeset in one or two columns; default is onecolumn.
oneside 	twoside 	 Selects one- or two-sided layout; default is oneside, except that in the book class the default is twoside.
For one-sided printing, the text is centered on the page. For two-sided printing, the \evensidemargin (\oddsidemargin) parameter determines the distance on even (odd) numbered pages between the left side of the page and the text’s left margin, with \oddsidemargin being 40% of the difference between \paperwidth and \textwidth, and \evensidemargin is the remainder.
openright 	openany 	Determines if a chapter should start on a right-hand page; default is openright for book, and openany for report.
The slides class offers the option clock for printing the time at the bottom of each note.
Additional packages are loaded like this:

\usepackage[options]{pkg}

To specify more than one package, you can separate them with a comma, as in \usepackage{pkg1,pkg2,...}, or use multiple \usepackage commands.
Any options given in the \documentclass command that are unknown by the selected document class are passed on to the packages loaded with \usepackage.