%%
%% The LaTeX Companion, 3ed
%%
%% Example 9-6-18 on page I-722 in "Adjusting the font kerning".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

  %!TEX program = lualatex

  \setlength\parindent{0pt}

%StartShownPreambleCommands
\usepackage{fontspec}
\newfontfamily\headfamily{Playfair Display}
%StopShownPreambleCommands

\begin{document}
\fontsize{12}{14}\headfamily       AN (ALL-CAPS) HEADING \\
\addfontfeature{Style=Uppercase}   AN (ALL-CAPS) HEADING \\
\addfontfeature{Kerning=Uppercase} AN (ALL-CAPS) HEADING
\end{document}