Please leave a comment or edit the answer if I made a mistake or do not follow best practices.
Solution for article Class
Thanks, @UlrikeFischer for the hint.
\documentclass{article}
% Small pages for demo purposes.
\usepackage[a6paper]{geometry}
\usepackage{blindtext}
% "bookmarksnumbered" is optional: It adds the heading number to the bookmark.
\usepackage[bookmarksnumbered]{hyperref} % or "bookmark" package
\begin{document}
\tableofcontents
% Start
% --- ---
\setcounter{secnumdepth}{-1}
\section{Thanks} % <-- Replace "Thanks" with your heading title.
\sectionmark{Thanks} % <-- Replace "Thanks" with your heading title.
\setcounter{secnumdepth}{2}
% --- ---
% End
\blindtext
\section{Introduction}
\subsection{SubSection}
\blindtext
\end{document}

Solution for book or report Class
Thanks, @UlrikeFischer for the hint.
\documentclass{book} % or "report"
% Small pages for demo purposes.
\usepackage[a6paper]{geometry}
\usepackage{blindtext}
% "bookmarksnumbered" is optional: It adds the heading number to the bookmark.
\usepackage[bookmarksnumbered]{hyperref} % or "bookmark" package
\begin{document}
\tableofcontents
% Start
% --- ---
\setcounter{secnumdepth}{-1}
\chapter{Thanks} % <-- Replace "Thanks" with your heading title.
\chaptermark{Thanks} % <-- Replace "Thanks" with your heading title.
\setcounter{secnumdepth}{2}
% --- ---
% End
\blindtext
\chapter{Introduction}
\section{Section}
\blindtext
\end{document}

Solution for scrartcl KOMA Class
\documentclass{scrartcl}
% Small pages for demo purposes.
\usepackage[a6paper]{geometry}
\usepackage{blindtext}
% "bookmarksnumbered" is optional: It adds the heading number to the bookmark.
\usepackage[bookmarksnumbered]{hyperref} % or "bookmark" package
\begin{document}
\tableofcontents
% Start
% --- ---
\addsec{Thanks} % <-- Replace "Thanks" with your heading title.
% --- ---
% End
\blindtext
\section{Introduction}
\subsection{SubSection}
\blindtext
\end{document}

Solution for scrbook or scrreport KOMA Class
\documentclass{scrbook} % or "scrreport"
% Small pages for demo purposes.
\usepackage[a6paper]{geometry}
\usepackage{blindtext}
% "bookmarksnumbered" is optional: It adds the heading number to the bookmark.
\usepackage[bookmarksnumbered]{hyperref} % or "bookmark" package
\begin{document}
\tableofcontents
% Start
% --- ---
\addchap{Thanks} % <-- Replace "Thanks" with your heading title.
% --- ---
% End
\blindtext
\chapter{Introduction}
\section{Section}
\blindtext
\end{document}
