\footnote[number]{text}
The \footnote command places the numbered footnote text at the bottom
of the current page. The optional argument, number, is used to change
the default footnote number. This command can only be used in outer
paragraph mode.
\footnotemarkThe \footnotemark command puts the footnote number in the text. This command can be used in inner paragraph mode. The text of the footnote is supplied by the \footnotetext command.
\footnotetext[number]{text}
The \footnotetext command produces the text to be placed at the bottom
of the page. This command can come anywhere after the \footnotemark
command. The \footnotetext command must appear in outer paragraph
mode.
The optional argument, number, is used to change the default footnote number.