How many columns is that one page?
By default, a Word document is a 1-column document. The number of columns is
a section formatting feature. Thus, you can separate a multi-column section
from a single column section by inserting a section break, and then setting
the number of columns in each section independently.
For example, a document might have the following structure:
{one column of text, otherwise known as a normal Word document}
{section break}
{three columns of text, sometimes known as newspaper or snaking columns}
{section break}
{one column of text, otherwise known as a normal Word document}
To insert a section break, from the menu, choose Insert - Break - and a
section section break. If you choose Continuous, you can have it change
columns within a page. If you use a Next Page break, then the page that
follows the current one will show the change. After inserting a break,
you'll need to set the number of columns in the new section to the number
desired.