usepackage

usepackage is a LaTeX command that loads extensions called packages. Packages provide additional features such as enhanced math formatting, graphics inclusion, bibliography styles, font support, and language handling. It is used in the preamble of a LaTeX document, after \documentclass{...} and before \begin{document}.

Syntax: \usepackage[options]{package}. Multiple packages may be loaded in separate calls or in a single call by listing them separated by commas: \usepackage{amsmath,graphicx}. Packages may depend on others and can alter global document settings; some packages also accept driver or compatibility options.

Option arguments configure package behavior; common examples include babel with language options, inputenc for character encoding, fontenc for font encoding, geometry for page layout, hyperref for hyperlinks, and graphicx for image inclusion. Some packages require specific driver options or are sensitive to the engine in use (pdflatex, xelatex, or lualatex), which can affect how files are processed or rendered.

Installation and usage: Most TeX distributions include thousands of packages, which can be installed or updated via a package manager such as TeX Live Manager or MiKTeX Package Manager. If a requested package is not installed, the compiler may prompt for installation. Documentation for each package is typically available on CTAN and in the package’s own documentation; additional guidance can be found in LaTeX project wikis and on TeX Stack Exchange.