I'd like to know why does my index prints in an alphabetical order.
EDIT:
\documentclass[a4paper]{article}
\usepackage[portuguese]{babel}
\usepackage[utf8]{inputenc}
\usepackage{indentfirst}
\usepackage{graphicx}
\usepackage{verbatim}
\usepackage{indentfirst}
\usepackage{setspace}
\usepackage[export]{adjustbox}
\usepackage{makeidx}
\makeindex
\begin{document}
\setlength{\textwidth}{16cm}
\setlength{\textheight}{22cm}
\title{....} %stuff here
\author{....} %more stuff
\maketitle
\thispagestyle{empty}
\newpage
\printindex
\section{Introdução}
\index{Introdução}
\begin{small}
\onehalfspacing
Introduction text
\end{small}
%\sections all over the document in \index{Introduction}
\end{document}
Best Regards