Margins are invisible lines that keep text away from the edges of the page. There are preset margins at the top, bottom, left and right. The margins at the top and bottom allow room for headers and footers.
Change Margins for the Whole Document
To change Margins for the entire document, choose File/Page Setup and change the numbers. Be sure that Whole document is selected in the Apply To box. As soon as you make a change, the effect can be seen in the Preview area.
To change the default margins for all your documents, select File/Page Setup, set your margins and click Default. Word will now apply your new margin settings to all the documents created with that same template.
Drag the Margin Markers
To change margins, you can also highlight your text and drag the margin markers on the ruler just like you do on an electric typewriter. There is an up-arrow marker for the right margin, but there are two arrows for the left margin. The down-arrow marker is for the first line of the paragraph, and the up-arrow is for the rest of the paragraph. They move independently so you can create an indent for the first line that is either in or out. When the first line extends farther to the left than the body of the paragraph, it is called a "hanging indent" or "hanging paragraph" as in the example below.
The hanging indent in this example is created by moving the down-arrow farther over to the left than the up-arrow.
Change Margins for a Section of Text
To change margins for a section of the document, highlight the text, and drag the margin markers to the new location.