Like numbered styles, footnote styles give the reference an ascending number in the text and the full references are listed in that order at the bottom of the page in a footnote. A full list at the end of the work or chapter may also be required - although unlike with numbered styles, this may be in alphabetical order by surname, rather than in order of mention.
The Chicago style is the most well-known footnote style. In Chicago and other footnote styles there are rules that apply if you use a work again in another footnote. Up until the Chicago 16th Edition, If you mention the citation again as the next footnote, then the term “ibid” (“in the same place”) is used instead of the reference. If it is used again after referring to a different citation, then a short form of the reference is used in the footnotes - the manual for the style will tell you what this should look like. However, this was changed in the Chicago 17th Edition, with the short form now favoured over ibid even if mentioned immediately afterwards.
In the text:
"As the global information landscape increasingly facilitates the sharing, re-purposing and dissemination of information, the ways in which students are accustomed to interacting with information resources are also changing"1.
As a footnote at the bottom of the page:
1 Adrian Stagg, Lindy Kimmins, and Nicholas Pavlovski, "Academic Style with Substance," The Electronic Library 31, no. 4 (2013). https://doi.org/10.1108/el-01-2012-0005.
(elements are separated by commas)
If used again, whether immediately or after other citations (note, this is a change from Chicago 16th):
2 Stagg, Kimmins, and Pavlovski, "Academic style with substance."
In the reference list, which is in alphabetical order:
Stagg, Adrian, Lindy Kimmins, and Nicholas Pavlovski. "Academic Style with Substance." The Electronic Library 31, no. 4 (2013): 452-64. https://doi.org/10.1108/el-01-2012-0005.
(first author’s name inverted, elements are separated by full stops)