http://web.image.ufl.edu/help/latex/margins.shtml
Changing the spacing on a document-wide basis is done for different document settings using different packages. The geometry package controls the overall margins and text area of the document. The package must be called in the preamble of the document and specified when called.
The geometry package is called with the use package command, followed by the options, and then the package name, like this:
usepackage[left=2cm,top=1cm,right=3cm,nohead,nofoot]{geometry}
