Use footnotes, cross-references, and links to point readers to useful, related information.
Avoid using footnotes; often, you can use a short parenthetical phrase or sentence instead of a footnote. Use a footnote only when including information inline disrupts continuity.
In printed information, use a superscript numeral to denote a footnote, and number footnotes sequentially throughout the information. If the information is divided into sections or chapters, restart the numbering in each section or chapter. If a superscript numeral might be mistaken for a mathematical symbol, use a dagger (†) if it is available, rather than a numeral or an asterisk.
Place a footnote number at the ...