documentclass[30pt]{report}
usepackage[a4paper,top=3cm,bottom=3cm,left=3cm,right=3cm]{geometry}
usepackage{graphicx}
begin{document}
  begin{figure}[h]
    centering includegraphics[width=5cm]{najah.png}
  end{figure}
  title{ATLAS Detector}
  author{Fatima Shahrouj\ Departement of physics, An-Najah National University NNU, Nablus, Palestine.}
  maketitle
end{document}

documentclass[30pt]{report}
usepackage[a4paper,top=3cm,bottom=3cm,left=3cm,right=3cm]{geometry}
usepackage{graphicx}
usepackage{titling}

begin{document}
  posttitle{
    includegraphics[width=5cm]{najah.png}
  end{center}
  }
  title{ATLAS Detector}
  author{Fatima Shahroujnewline Departement of physics, An-Najah National University NNU, Nablus, Palestine.}
maketitle

end{document}