\documentclass[12pt, letterpaper]{article}
% Set margins
\usepackage[left=2cm, right=2cm, top=2.5cm, bottom=2cm]{geometry}
% Font setup
\usepackage{times}
\fontsize{12pt}{15pt}\selectfont % The second value is the baseline skip, adjusted for better readability
% Single line spacing
\usepackage{setspace}
\singlespacing
% Color package
\usepackage{xcolor}
% Page number at the bottom center
\pagestyle{plain}
% Header and footer
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{} % Clear all headers and footers
\renewcommand{\headrulewidth}{0pt} % Remove the default line at the top
\rhead{\color{gray}Lastname, Firstname} % Right header with grey color
\chead{\color{gray}PIN} % Center header with grey color
\lfoot{\color{gray}Title of Document} % Left footer with grey color
\cfoot{\color{gray}\thepage} % Center footer with grey color and page number
% \rhead{\vspace{2\baselineskip}Lastname, Firstname} % Right header moved 2 lines down
% \chead{\vspace{2\baselineskip}PIN} % Center header moved 2 lines down
% \lfoot{Title of Document} % Left footer
% \cfoot{\thepage} % Center footer with page number
% Adjust the separation between the header and the main text
% \setlength{\headsep}{1.5cm}
% Adjusting section and subsection font sizes
\usepackage{titlesec}
\titleformat{\section}
{\normalfont\fontsize{12}{15}\bfseries}{\thesection}{1em}{}
\titleformat{\subsection}
{\normalfont\fontsize{12}{15}\bfseries}{\thesubsection}{1em}{}
\begin{document}
Your content goes here...
\section{Introduction}
This is the introduction section. It provides an overview of the document's content.
\section{Main Content}
\subsection{Topic A}
This is the first topic under the main content. Here are some key points:
\begin{enumerate}
\item First numbered point.
\item Second numbered point.
\item Third numbered point.
\end{enumerate}
\subsection{Topic B}
This is the second topic under the main content. Here are some bullet points:
\begin{itemize}
\item First bullet point.
\item Second bullet point.
\item Third bullet point.
\end{itemize}
\section{Further Discussions}
\subsection{Subtopic X}
This is a subtopic under further discussions.
\subsection{Subtopic Y}
Another subtopic under further discussions.
\section{Conclusion}
This is the conclusion section, summarizing the main points of the document.
\end{document}