Footnotes contain explanations or notes about the text. They are usually at the end of a page, but they DO belong to the type area.

Most times, footnotes are 1 - 2 font sizes smaller than standard text, but should conform to its respective style.

Within the continuous text, the referenced terms are flagged by a number. This number, or footnote, is also placed at the end of the page, and followed by the footnote text.

Footnotes should have the same line spacing and indentations as the standard text.

Furthermore, footnotes almost always appear on the same page as the referenced passage. An exception is demonstrated by scientific works: If one page shows lots of footnotes, they may be evenly arranged on two pages.

In a nutshell: Footnotes lie within the type area, should conform with the basic text and there should be a new line for every footnote.