[Tex/LaTex] Remove first letter style

Question

I borrow a template on Overleaf for my report. However, I would like to change the first letter "N" back to ordinary letter style.

Thank you everyone!

New edition :
I am sorry for not including the code. The original code is also attached here.

\documentclass[11pt, titlepage]{article}

\usepackage[margin=1in]{geometry}
\usepackage[strict]{changepage}
\usepackage{float}
\usepackage{fancyhdr}
\usepackage{mhchem}
\usepackage{siunitx}
\usepackage{wrapfig, booktabs}
\usepackage{enumitem}
\usepackage{caption}
\usepackage{commath}
\usepackage{amsmath}
\usepackage[hang]{footmisc}
\usepackage{multicol}
\usepackage{amsfonts}
\usepackage{mathrsfs}
\usepackage{graphicx}
\usepackage[]{algorithm2e}
\usepackage{subcaption}

\newcommand{\experimentDate}{2015-2016
\author{Student}
\newcommand{\authorLastName}{Student}
\title{Title}

\date{\parbox{\linewidth}{}}

%\pagestyle{fancy}
\fancyhf{}
\rhead{\authorLastName\ \thepage}
\lhead{\experimentShortName}
\cfoot{\className\ -- \experimentNumber}

\usepackage{color}
\usepackage{sectsty}

\definecolor{WordSectionBlue}{RGB}{30, 90, 147}

\allsectionsfont{\color{WordSectionBlue}}

\newcommand{\gpmol}{\si{\gram\per\mol}}

\begin{document}
    \maketitle
    \setcounter{tocdepth}{1}
    \section{Introduction}
    \subsection{Aim}
    \begin{paragraph}
    Nonlinear dynamics has diverse applications, ranging from medical diagnosis to computer encryption.
    \end{paragraph}
\end{document}

Answer 1

You may be misusing the \paragraph macro. \paragraph is a sectioning command -- like \section, \subsection, and \subsubsection. paragraph is not an environment pre-defined by LaTeX. It just so happens that because of the way that LaTeX handles the (otherwise) non-existent commands \begin{paragraph} and \end{paragraph}, you're not encountering an immediate error message.

In TeX and LaTeX, paragraphs (the typographic units) are blocks of text; they do not need to be encased in \begin{paragraph} and \end{paragraph} statements.

Here's a simplified version of your code, with the \begin{paragraph} and \end{paragraph} instructions removed.

\documentclass[11pt, titlepage]{article}

\usepackage[margin=1in]{geometry}
\usepackage{color}
\definecolor{WordSectionBlue}{RGB}{30, 90, 147}
\usepackage{sectsty}
\allsectionsfont{\color{WordSectionBlue}}

\begin{document}

\section{Introduction}

\subsection{Aim}

Nonlinear dynamics has diverse applications, ranging from 
medical diagnosis to computer encryption.

\end{document}