# Missing space after Appendix

I am working on a document that has an appendix. I would like it to have the heading: "Appendix A. Tasks for Progressive Formulation"

This is the code I am using

 \appendix

\newpage

\section{Tasks for Progressive Formulation}


The result I get is missing the space between the word Appendix and the letter A. It shows like this:

AppendixA. Tasks for Progressive Formulation

How can I force a white space between Appendix and the letter?

Edit: more code

\documentclass{elsarticle}

\usepackage[english]{babel}
\usepackage{booktabs}
\usepackage[autostyle, english = american]{csquotes}
\usepackage{float}
\restylefloat{figure}
\usepackage[margin=3cm]{geometry}
\usepackage{graphicx}
\usepackage{lineno}
\usepackage{multirow}
\usepackage{natbib}
\usepackage{tabulary}

\begin{document}

\appendix
\newpage
\section{Tasks for Progressive Formulation}
\end{document}


It's a wrong choice by elsarticle.cls that has

\def\appendixname{Appendix }


with a space, whereas babel correctly does

\renewcommand{\appendixname}{Appendix}


with no space. You can reinstate the behavior expected by elsarticle doing

\addto\captionsenglish{\renewcommand{\appendixname}{Appendix }}


Here's a minimal example (the other packages you load have nothing to do with the issue) But, really, elsarticle should do di \documentclass{elsarticle}

\usepackage[english]{babel}

\begin{document}

\appendix
\section{Tasks for Progressive Formulation}
\end{document}


But, really, elsarticle should do differently: the code from line 748 to line 758 in elsarticle.cls should be

\renewcommand\appendix{\par
\setcounter{section}{0}%
\setcounter{subsection}{0}%
\setcounter{equation}{0}
\gdef\thefigure{\@Alph\c@section.\arabic{figure}}%
\gdef\thetable{\@Alph\c@section.\arabic{table}}%
\gdef\thesection{\appendixname\space\@Alph\c@section}%
\gdef\theequation{\@Alph\c@section.\arabic{equation}}%
}


without a redefinition of \appendixname and adding the space in the redefinition of \thesection. A fixed tag should be just a tag, with no “formatting instructions” that belong elsewhere.

Please try the following MWE (I reduced your code a little bit to make it minimal):

\documentclass{elsarticle}

\usepackage[english]{babel}
\usepackage[margin=3cm]{geometry}

\usepackage{blindtext}  % dummy text

\begin{document}
\blindtext % dummy text
\appendix
\renewcommand*{\thesection}{\appendixname~\Alph{section}}
\section{Tasks for Progressive Formulation}
\blindtext
\subsection{Test}
\blindtext
\end{document}



Result: