Moving the beginning of a footnote to the right

Question

I would like that the numbers "2, 3, 4, 5, 6" start from the same position as the number "1" in the previous footnote.

\documentclass{article}

\usepackage{hyperref}
\usepackage{xparse}

\ExplSyntaxOn

\NewDocumentCommand \footnotenumber { O{} }
  {
    \footnotemark
      {
        \tl_if_blank:nF { #1 }
          {
            \addtocounter { footnote } { -1 }
            \refstepcounter { footnote }
            \label { #1 }
          }
      }
  }

\NewDocumentCommand \footnotemultiple { O{} m }
  {
    \group_begin:
    \tl_if_blank:nF { #1 }
      {
        \clist_clear:N \l_tmpa_clist
        \clist_map_inline:nn { #1 }
          {
            \clist_put_right:Nn \l_tmpa_clist { \ref{ ##1 } }
          }
        \def \thefootnote { \clist_use:Nn \l_tmpa_clist { , } }
      }
    \footnotetext { #2 }
    \group_end:
  }

\ExplSyntaxOff


\begin{document}

Lorem ipsum dolor sit amet, consectetur\footnote{Morbi ac rhoncus mi, at porttitor erat. Aliquam fringilla erat nec tortor placerat ullamcorper.} adipiscing\footnotenumber[fn1] elit. Nunc non nisl\footnotenumber[fn2] sed orci suscipit porta\footnotenumber[fn3]. Nulla et arcu placerat\footnotenumber[fn4], vehicula lorem id, imperdiet ante. Aenean\footnotenumber[fn5] et tortor purus.

\footnotemultiple[fn1,fn2,fn3,fn4,fn5]{Etiam porttitor bibendum neque et luctus. Ut volutpat, erat vitae dapibus condimentum, eros nunc suscipit eros, id imperdiet lectus massa eget metus.}

\end{document}

P. S. This way of numbering footnotes is shown here.

Answer 1

Update 2022/05/28

There shall soon be a new package multifootnote on CTAN. The answer of this question corresponds to the two package options:

---

Normally the footnote is typeset with list, where the label width is fixed. However, you can completely redefine this behavior by modifying \@makefntext. Notice that the @ here means that you need \makeatletter.

\documentclass{article}

\usepackage{hyperref}
\usepackage{xparse}

\makeatletter
\ExplSyntaxOn

\renewcommand{\@makefntext}[1]{
    \parbox{0pt}{\@makefnmark} \nobreakspace #1
}

\NewDocumentCommand \footnotenumber { O{} }
  {
    \footnotemark
      {
        \tl_if_blank:nF { #1 }
          {
            \addtocounter { footnote } { -1 }
            \refstepcounter { footnote }
            \label { #1 }
          }
      }
  }

\NewDocumentCommand \footnotemultiple { O{} m }
  {
    \group_begin:
    \tl_if_blank:nF { #1 }
      {
        \clist_clear:N \l_tmpa_clist
        \clist_map_inline:nn { #1 }
          {
            \clist_put_right:Nn \l_tmpa_clist { \ref*{ ##1 } }
          }
        \def \thefootnote { \clist_use:Nn \l_tmpa_clist { , } }
      }
    \footnotetext { #2 }
    \group_end:
  }

\ExplSyntaxOff
\makeatother

\begin{document}

Lorem ipsum dolor sit amet, consectetur\footnote{Morbi ac rhoncus mi, at porttitor erat. Aliquam fringilla erat nec tortor placerat ullamcorper.} adipiscing\footnotenumber[fn1] elit. Nunc non nisl\footnotenumber[fn2] sed orci suscipit porta\footnotenumber[fn3]. Nulla et arcu placerat\footnotenumber[fn4], vehicula lorem id, imperdiet ante. Aenean\footnotenumber[fn5] et tortor purus.

\footnotemultiple[fn1,fn2,fn3,fn4,fn5]{Etiam porttitor bibendum neque et luctus. Ut volutpat, erat vitae dapibus condimentum, eros nunc suscipit eros, id imperdiet lectus massa eget metus.}

\end{document}

---

If you wish to indent the first line of each footnote, simply add a \hspace* in the command.

\renewcommand{\@makefntext}[1]{
    \hspace*{1.5em}
    \parbox{0pt}{\@makefnmark} \nobreakspace #1
}