\documentclass[a4paper, 12pt, english]{article}
\usepackage{lmodern}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\usepackage{babel}
\begin{document}
\thispagestyle{empty}

This is text in normal font size.

\fontsize{1cm}{0.9cm}\selectfont
This is a ginormous passage.

\normalsize
Back to normal.

\end{document}