empty header only for chapter pages

Question

I need to create my document without header only for chapter pages, but footer is same for all pages...what I need to do for that?

I used \usepackage{fancyhdr} and

\documentclass[12pt,a4paper,oneside]{report}

\begin{document}
\pagestyle{fancy}
\lhead{}
\chead{}
\rhead{INTRODUCTION }
\lfoot{Department cdo}
\cfoot{}
\rfoot{\thepage}

..........
...........
\end{spacing}
\end{document}

Answer 1

The standard way would be this one. With \leftmark you refer to the current chapter title. Since you're using 12pt type, also the \headheight needs to be adjusted.

\documentclass[12pt,a4paper,oneside]{report}
\usepackage{fancyhdr}

\setlength{\headheight}{14.5pt}
\pagestyle{fancy}
\fancyhf{}                    % clear all fields
\fancyhead[R]{\leftmark}      % right header
\fancyfoot[L]{Department cdo} % left footer
\fancyfoot[R]{\thepage}       % right footer

\fancypagestyle{plain}{% chapter pages use style plain
  \renewcommand{\headrulewidth}{0pt} % no top rule
  \fancyhf{}%                    clear all fields
  \fancyfoot[L]{Department cdo}% left footer
  \fancyfoot[R]{\thepage}%       right footer
}

\usepackage{lipsum} % mock text

\begin{document}
\chapter{Chapter}
\lipsum
\end{document}

If you want to change the font size in the footer, just use something like

\fancyfoot[L]{\footnotesize Department cdo} % left footer
\fancyfoot[R]{\footnotesize \thepage}       % right footer

in both places.