Footnote without reference in text

Question

I want to have a footnote (numbered) in the footnote section but don't want the footnote mark to appear in the written text. How can I achieve this behaviour? If I use \footnotetext the numbering doesn't stay consistent (once used and not referenced, i.e. no matching \footnotemark, the number stays the same).

Answer 1

If you don't use \footnotemark, but want the footnote number continued, you have to use \stepcounter{footnote} to increase the footnote counter yourself:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{mwe}
\begin{document}
\lipsum[1]\footnote{This was the first lipsum paragraph}

\lipsum[2]\stepcounter{footnote}\footnotetext{\label{ftn}We also have had assecond one.}

\lipsum[3]\footnote{And a third one.}

The invisible footnote was number \ref{ftn}.
\end{document}

Usually you don't need \refstepcounter, even if you set a label inside \footnotetext. I've shown this also in the example.

Note: Inside a minipage environment, you have to increase mpfootnote instead of footnote:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{mwe}
\begin{document}
\begin{figure}
  \begin{minipage}{\textwidth}
    \lipsum[1]\footnote{This was the first lipsum paragraph}
    
    \lipsum[2]\stepcounter{mpfootnote}\footnotetext{\label{ftn}We also have had assecond one.}
    
    \lipsum[3]\footnote{And a third one.}
    
    The invisible footnote was number \ref{ftn}.
  \end{minipage}
  \caption{Testfigure}
\end{figure}
\end{document}

---

Edit (because of comment): If you really need to use \footnotetext without \footnotemark but with \footref or \ref to a label set inside \footnotetext (something I would not recommend, because it is inconsistent and strange), you could locally redefine \thefootnote:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[colorlinks]{hyperref}
\usepackage{mwe}
\newcommand*{\footnotenomark}[1]{%
  {\renewcommand*{\thefootnote}{}\footnotemark}%
  \footnotetext{#1}%
}
\begin{document}
\lipsum[1]\footnote{This was the first lipsum paragraph}
\lipsum[4-7]

\lipsum[2]\footnotenomark{\label{ftn}We also have
  a second one.}
\lipsum[4-6]

\lipsum[3]\footnote{And a third one.}

\lipsum[4-5]
The invisible footnote was number \ref{ftn}.
\end{document}

But note, if you do not use option colorlinks but link frames or underlining links, there would be strange empty frames or underscores.

Answer 2

Here, I defined a new command that uses footnotetext and simply adds one to the counter that keeps track of footnote numbering.

\documentclass[10pt,a4paper]{article}

\newcommand{\invisiblefootnote}[1]{%
\addtocounter{footnote}{1}%
\footnotetext{#1}%
}

\begin{document}
  \footnote{Text 1}
  \footnote{Text 2}
  \invisiblefootnote{can't see this one}
  \footnote{another one}
\end{document}