\documentclass[12pt|landscape]{article}You could use other than 12pt or article. Then in PCTex, go to the top menu, choose
...
\oddsidemargin 0in
\textwidth 9in
\topmargin -0.5in
\textheight 6.5in
...
\begin{document}
\Large
...
\end{document}
Settings|Default Settings|Viewer|LandscapeIt will be useful to use \Large somewhere in the Latex document to enlarge the lettering.