% Free sample plain TeX file from 99helpers.com/file-types/tex
% Plain TeX is Knuth's own macro set, without LaTeX.
% Build it with:  pdftex sample-plain.tex   (or: tex sample-plain.tex for DVI)
\font\titlefont=cmbx12 at 14pt  % load a font at a size, under a new name
\parindent=0pt            % no paragraph indentation
\parskip=6pt              % a little space between paragraphs

{\titlefont Hello from plain \TeX}

This file uses no LaTeX: no document class, no packages, no
{\tt\char`\\begin\char`\{document\char`\}}. It is the
smallest kind of \TeX\ document that still shows text and maths:
$a^2 + b^2 = c^2$ inline, and on a line of its own
$$\sum_{k=1}^{n} k = {n(n+1) \over 2}.$$

Free sample from 99helpers.com/file-types/tex.

\bye % ends the job: ships out the last page and stops