\documentclass[a4paper]{book}
\usepackage{latexsym,amsmath,amssymb}
\usepackage[top=2cm,bottom=1.3cm,left=4cm,right=5cm,bindingoffset=0.25in,heightrounded,marginparwidth=4cm,marginparsep=3mm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{marginnote}
\usepackage{xcolor}
\usepackage{titlesec}
\colorlet{sectitlecolor}{red!60!black}
\colorlet{sectboxcolor}{cyan!30}
\colorlet{secnumcolor}{orange}
\titleformat{\section}
{\normalfont\Large\bfseries\color{sectitlecolor}}{\llap{\makebox[3em][l]{\colorbox{sectboxcolor}{\textcolor{secnumcolor}{\thesection}}}}}{0em}{}
% % % % % % % % % % % % % % % % % % % % % % % % % % %
\begin{document}
\chapter{A test chapter}
This is the first chapter
\newgeometry{top=2cm,bottom=1.3cm,left=4cm,right=2cm}
\section{First section}
This is the first section without marginal note.
\restoregeometry
\section{Second section}
This is the second section with marginal note.\reversemarginpar\marginnote{\textcolor{blue}{This is a margin note.}}
\newgeometry{top=2cm,bottom=1.3cm,left=4cm,right=2cm}
\section{Third section}
This is the third section without marginal note.
\restoregeometry
\section{Fourth section}
This is the fourth section with marginal note.\reversemarginpar\marginnote{\textcolor{blue}{This is a margin note.}}
\end{document}
When I use the above, each section is printed in separate pages. I want this type of texts. Is it possible to print continuously, not in separate pages

\newgeometry. What are you trying to achieve with those commands? – Gonzalo Medina Sep 21 '15 at 16:32