In Word margins are a section property, so you don't change "margins" for a
paragraph; you change "indents." The best way to do this is with a style,
but you can also use direct formatting. You can use either the ruler (see
http://word.mvps.org/faqs/formatting/UsingRulers.htm) or the Format |
Paragraph dialog. To make the paragraph justified, use the Paragraph dialog
or the Justify button on the Formatting toolbar.