%%
%% The LaTeX Companion, 3ed
%%
%% Example 3-5-13 on page I-213 in "footmisc --- Various footnotes styles".
%%
%% 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{100.80103pt}
\setlength\textheight{4.7\baselineskip}

\newcommand\sampletext{Some
  text\footnote{A first.} with a footnote.
  More text.\footnote{A second footnote with
    a few lines of text to show variations
    in the footnote line-breaking behavior.}
  Even more text.\footnote{A third note.}
  Some final text.}


%StartShownPreambleCommands
  \usepackage{footmisc}
  \setlength\footnotemargin{10pt}
%StopShownPreambleCommands

\begin{document}

  \sampletext  % as defined above

\end{document}