A margin may refer to any of the following:
1. A margin is a space separating text or other elements from the edge of the paper commonly adjusted through the page setup. Most programs allow for the top, bottom, left, and right margins to be set. The standard margin settings are 1" top and bottom and 1.25" left and right.
The picture above is an example of a document with each of the margins shown in red.
How does adjusting the margins affect the text?
By increasing the size of the margins, you decrease the available space on the page that text can occupy. In other words, a page with bigger margins have less room for text. If you decrease the size of the margins, the page can accept more text.
2. With CSS, a margin is a white space around an element or another object on a web page. The picture below helps demonstrate the difference between padding and a margin when working with CSS. As can be seen, the padding is in the border, and the margin is outside the border.