How to reduce page margins in LaTeX using the geometry package

To set or reduce the page margin (white space between the border of the page and the text) you can use the geometry package.

Set margin of all sides to 2cm:

\usepackage[left=20mm, right=20mm, top=20mm, bottom=20mm]{geometry}

To set just the left and right margin to 2cm, use

\usepackage[left=20mm, right=20mm]{geometry}