Bold, italics and underlining

\documentclass{article}
\begin{document}

This is \textbf{bold text} in a sentence.

\textbf{This entire sentence is bold.}

You can \textbf{nest other commands like \textit{italic} inside bold}.

\end{document}

\documentclass{article}
\begin{document}

This is \textit{italic text} in a sentence.

\textit{This entire sentence is italicized.}

LaTeX uses \textit{emphasis} for semantic meaning.

\end{document}

\documentclass{article}
\begin{document}

This is \underline{underlined text} in a sentence.

\underline{This entire sentence is underlined.}

% Note: Underlining can look messy with descenders
The letters \underline{g, j, p, q, y} have descenders.

\end{document}

\documentclass{article}
\begin{document}

% Bold and italic
\textbf{\textit{Bold and italic text}}

% Italic and underlined
\textit{\underline{Italic and underlined}}

% All three
\textbf{\textit{\underline{Bold, italic, and underlined}}}

% Alternative nesting order (same result)
\underline{\textbf{\textit{Also all three formats}}}

\end{document}

\documentclass{article}
\begin{document}

% Normal emphasis (produces italic)
This is \emph{emphasized text}.

% Nested emphasis (toggles back to normal)
\emph{This is italic with \emph{nested} emphasis.}

% Emphasis is semantic - it adapts to context
\textit{In italic text, \emph{emphasis} becomes upright.}

\end{document}

\documentclass{article}
\begin{document}

% Small capitals
\textsc{Small Capitals Look Like This}

% Useful for names and acronyms
\textsc{nasa} announced the launch.

Written by \textsc{John Smith}, \textsc{phd}.

\end{document}

\documentclass{article}
\begin{document}

% Monospace font for code
Type \texttt{latex document.tex} to compile.

% File paths
Save your file as \texttt{/home/user/document.tex}

% Inline code
The \texttt{\\textbf} command makes text bold.

\end{document}

\documentclass{article}
\begin{document}

% Sans serif text
\textsf{This is sans serif text.}

% Useful for modern look
\textsf{\textbf{Bold Sans Serif Heading}}

\end{document}

\documentclass{article}
\begin{document}

% Slanted is different from italic
\textsl{This is slanted text.}

Compare: \textit{italic} vs \textsl{slanted}

\end{document}

\documentclass{article}
\begin{document}

{\large \textbf{Large Bold Text}}

{\Large \textit{Even Larger Italic}}

{\small \texttt{Small monospace text}}

% Size commands from smallest to largest:
{\tiny tiny}
{\scriptsize scriptsize}
{\footnotesize footnotesize}
{\small small}
{\normalsize normalsize}
{\large large}
{\Large Large}
{\LARGE LARGE}
{\huge huge}
{\Huge Huge}

\end{document}

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

% Basic colors
\textcolor{red}{Red text}
\textcolor{blue}{\textbf{Bold blue text}}
\textcolor{green}{\textit{Italic green text}}

% Custom colors
\definecolor{myorange}{RGB}{255, 96, 55}
\textcolor{myorange}{Custom orange color}

% Highlighting
\colorbox{yellow}{Highlighted text}

\end{document}

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

% Strikethrough
\st{This text is struck through}

% Highlighting with soul package
\hl{This text is highlighted}

% Letter spacing
\so{SPACED OUT TEXT}

\end{document}

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

% Normal underline
\uline{Better underline with ulem}

% Double underline
\uuline{Double underlined text}

% Wavy underline
\uwave{Wavy underline for errors}

% Strike out
\sout{Struck out text}

\end{document}

\documentclass{article}
\begin{document}

% Bold environment
\begin{bfseries}
This entire paragraph is bold. You can write multiple sentences
and they will all be bold. This is useful for longer passages.
\end{bfseries}

% Italic environment
\begin{itshape}
This entire paragraph is in italics. Every sentence here
will be italicized until we close the environment.
\end{itshape}

% Typewriter environment
\begin{ttfamily}
This looks like computer code.
All text here is monospaced.
\end{ttfamily}

\end{document}

\documentclass{article}
\begin{document}

% Declarations affect all following text
{\bfseries Bold text using declaration}

{\itshape Italic text using declaration}

{\bfseries\itshape Bold and italic together}

% Limiting scope with braces
Normal text {\sffamily sans serif text} normal again

\end{document}

\documentclass{article}
\begin{document}

\textbf{\large 1. Introduction}

This section introduces the topic with \emph{emphasis} on key concepts.

\textbf{Key Terms:}
\begin{itemize}
\item \textbf{LaTeX:} A typesetting system
\item \textbf{Markup:} Text with formatting codes
\item \textbf{Compiler:} Processes \texttt{.tex} files
\end{itemize}

\end{document}

\documentclass{article}
\begin{document}

According to \textit{Smith et al.} (2023), the results were 
\textbf{statistically significant} (p < 0.05).

\emph{Note:} These findings contradict earlier work by 
\textsc{Johnson} (2020).

\end{document}