How to Write a Footnote?

How to write the footnote is going to depend on a couple of things. Is it informational or to cite a source? If informational, just put the information and any need citation. If it is a citation, you need to know what format. Different subjects use different formats, so adding the subject (history, science, etc) to your search will give you detailed information. Generally, you want to put the author, title, and page number.