LaTeX Fonts Guide: Change Font Family, Size, and System Fonts

\documentclass{article}
\begin{document}

% Family (shape of letters)
\textrm{Roman family (serif)}
\textsf{Sans serif family}
\texttt{Typewriter family (monospace)}

% Series (weight/width)
\textmd{Medium series (normal)}
\textbf{Bold series}

% Shape (slant/style)
\textup{Upright shape}
\textit{Italic shape}
\textsl{Slanted shape}
\textsc{Small Caps Shape}

\end{document}

% All combinations work
\textsf{\textbf{Sans serif bold}}
\texttt{\textit{Typewriter italic}}
\textrm{\textbf{\textit{Roman bold italic}}}
\textsc{\textbf{Bold Small Caps}}

% Using declarations
{\sffamily\bfseries\itshape Sans serif bold italic}

\documentclass{article}

% Times-like fonts
\usepackage{mathptmx}  % Times with math support
% or
\usepackage{newtxtext,newtxmath}  % New TX fonts

% Palatino-like fonts
\usepackage{mathpazo}  % Palatino with math
% or
\usepackage{newpxtext,newpxmath}  % New PX fonts

% Computer Modern variants
\usepackage{lmodern}   % Latin Modern
\usepackage{cm-super}  % CM Super

% Sans serif as default
\usepackage{helvet}
\renewcommand{\familydefault}{\sfdefault}

% Other popular choices
\usepackage{fourier}   % Utopia
\usepackage{libertine} % Linux Libertine
\usepackage{kpfonts}   % KP Fonts

\begin{document}
Your text here...
\end{document}

\documentclass{article}
\usepackage{fontspec}

% Set main font
\setmainfont{Times New Roman}
\setsansfont{Arial}
\setmonofont{Consolas}

% With options
\setmainfont{Georgia}[
  BoldFont = Georgia Bold,
  ItalicFont = Georgia Italic,
  BoldItalicFont = Georgia Bold Italic
]

% Alternative syntax
\setmainfont[
  Ligatures=TeX,
  Numbers=OldStyle,
  Scale=1.0
]{Minion Pro}

\begin{document}
This document uses system fonts directly!
\end{document}

\documentclass{article}
\usepackage{fontspec}

% Define custom font commands
\newfontfamily\headingfont{Helvetica Neue}
\newfontfamily\specialfont{Zapfino}
\newfontfamily\codefont{Source Code Pro}

\begin{document}

{\headingfont\Large This is a heading in Helvetica Neue}

Regular text in the main font.

{\specialfont Special decorative text}

{\codefont\small Code examples in Source Code Pro}

\end{document}

\documentclass{article}
\usepackage{fontspec}

\setmainfont{EB Garamond}[
  Ligatures={Common, Rare},
  Numbers=OldStyle,
  Contextuals=Alternate,
  Style=Historic
]

% Specific features
\newfontfamily\displayfont{Adobe Garamond Pro}[
  Numbers={Proportional,OldStyle},
  Letters=SmallCaps,
  Ligatures={Common,Discretionary}
]

\begin{document}

% Ligatures
Office, shelf, affiliate (fi, fl, ffi ligatures)

% Old style numbers
Regular: 0123456789 vs {\addfontfeatures{Numbers=OldStyle}0123456789}

% Small caps
{\scshape Small Capitals Text}

% Stylistic sets
{\addfontfeatures{StylisticSet=1}Stylistic Variant}

\end{document}

\documentclass{article}
\usepackage{microtype}

% Full features (pdfLaTeX)
\usepackage[
  protrusion=true,
  expansion=true,
  tracking=true,
  kerning=true,
  spacing=true
]{microtype}

% Fine-tuning
\microtypesetup{
  protrusion={true,alltext},
  expansion={true,alltext,compat}
}

\begin{document}
Microtype improves typography through:
\begin{itemize}
\item Character protrusion (margin kerning)
\item Font expansion (better justification)
\item Tracking (letter spacing)
\item Additional kerning
\end{itemize}

The improvements are subtle but create more professional results.
\end{document}

\documentclass[12pt]{article}  % Base size: 10pt, 11pt, or 12pt

% Exact sizes
\fontsize{14}{17}\selectfont  % 14pt font, 17pt baseline
This text is exactly 14 points.

% Relative sizes
{\tiny Tiny text (5pt at 10pt base)}
{\small Small text (9pt at 10pt base)}
{\large Large text (12pt at 10pt base)}
{\Huge Huge text (25pt at 10pt base)}

% Custom size commands
\newcommand{\customsize}{\fontsize{13}{16}\selectfont}
{\customsize Custom 13pt text}

% Matching text and math fonts
\usepackage{mathptmx}     % Times
\usepackage{mathpazo}     % Palatino
\usepackage{fourier}      % Utopia
\usepackage{newtxmath}    % Times (modern)
\usepackage{newpxmath}    % Palatino (modern)
\usepackage{eulervm}      % Euler math
\usepackage{stix2}        % STIX fonts

% Math alphabets
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{mathrsfs}     % \mathscr
\usepackage{bbm}          % \mathbbm

% Usage
$\mathbb{R}$, $\mathcal{A}$, $\mathscr{L}$, $\mathfrak{g}$

\documentclass{article}
\usepackage{unicode-math}

% Set math font
\setmathfont{XITS Math}
% or
\setmathfont{Latin Modern Math}
% or
\setmathfont{TeX Gyre Termes Math}

% With options
\setmathfont{Cambria Math}[
  Scale=MatchLowercase,
  math-style=ISO,
  bold-style=ISO
]

\begin{document}
Unicode math allows: $α + β = γ$ and $∫_0^∞ e^{-x²} dx = \frac{√π}{2}$
\end{document}

\documentclass{article}
\usepackage{lettrine}
\begin{document}

\lettrine[lines=3]{O}{nce upon a time}, in a land far away, 
there lived a typographer who loved beautiful drop caps. 
This elegant initial letter adds a classic touch to the 
beginning of chapters or sections.

\lettrine[lines=2,loversize=0.1]{T}{his} is a smaller drop cap.

\end{document}

\documentclass{article}
\usepackage{fontspec}  % XeLaTeX/LuaLaTeX

% Define special purpose fonts
\newfontfamily\chapterfont{Bebas Neue}
\newfontfamily\quotefont{Crimson Text}[Scale=1.1]
\newfontfamily\emojifont{Apple Color Emoji}  % or Noto Color Emoji

\begin{document}

{\chapterfont\Huge Chapter One}

{\quotefont\itshape "Beautiful typography is invisible, 
yet it shapes how we perceive the written word."}

{\emojifont 😊 📚 ✨}  % Emoji support!

\end{document}

% Font not found (XeLaTeX/LuaLaTeX)
\setmainfont{Arial}[
  Extension = .ttf,
  Path = /path/to/fonts/,
  UprightFont = *-Regular,
  BoldFont = *-Bold,
  ItalicFont = *-Italic
]

% Missing characters
\usepackage{textcomp}  % Additional symbols
\usepackage[T1]{fontenc}  % Better encoding

% Font substitution warnings
\usepackage{silence}
\WarningFilter{latexfont}{Font shape}

% Check available fonts (XeLaTeX/LuaLaTeX)
% Run in terminal: fc-list : family