\documentclass{report}
\usepackage{graphicx}
\usepackage{titlesec}
\usepackage{geometry}
  \geometry{a4paper, left=2 cm,right=3cm,top=3cm,bottom=3cm }
  \usepackage{ptext}



%------------------------------------------------------------------------------ماکرو مربوط به وسط چین کردن فهرست مطالب---------------
\makeatletter
\renewcommand*\l@chapter[2]{%
  \ifnum \c@tocdepth >\m@ne
    \addpenalty{-\@highpenalty}%
    \vskip 1.0em \@plus\p@
    \setlength\@tempdima{1.5em}%
    \begingroup
      \parindent \z@ \if@RTL\leftskip\else\rightskip\fi \@pnumwidth
      \parfillskip -\@pnumwidth
      \leavevmode \bfseries
      \advance\if@RTL\rightskip\else\leftskip\fi\@tempdima
      \hskip -\if@RTL\rightskip\else\leftskip\fi
      #1\nobreak\leaders\hbox{$\m@th
        \mkern \@dotsep mu\hbox{.}\mkern \@dotsep
        mu$}\hfill \nobreak\hb@xt@\@pnumwidth{\hss #2}\par
      \penalty\@highpenalty
    \endgroup
  \fi}
  
\renewcommand\tableofcontents{%
    \if@twocolumn
      \@restonecoltrue\onecolumn
    \else
      \@restonecolfalse
    \fi
    \centerline{\huge\bfseries\contentsname
        \@mkboth{%
           \MakeUppercase\contentsname}{\MakeUppercase\contentsname}}%
    \vskip 40\p@
    \@starttoc{toc}%
    \if@restonecol\twocolumn\fi
    }
    
    \renewcommand{\@starttoc}[1]{%
  \hboxR to \textwidth{عنوان \hfill صفحه} 
  \begingroup
    \makeatletter
    \@input{\jobname.#1}%
    \if@filesw
      \expandafter\newwrite\csname tf@#1\endcsname
      \immediate\openout \csname tf@#1\endcsname \jobname.#1\relax
    \fi
    \@nobreakfalse
  \endgroup}
  
\makeatother

%%%%%%%%%%%%%%%%%%%%%%%%%%
\titleformat{\chapter}[display]
  {\normalfont\huge\bfseries\centering}{\chaptertitlename\ \thechapter}{20pt}{\Huge}
  \titlespacing{\chapter}{3pc}{3cm}{1cm}[3pc]


%------------------------------------------------------------------------------ماکرو مربوط به صفحه گذاری فارسی---------------------------
\makeatletter
\def\@myabjad#1{\ifcase#1\or الفـ\or ب\or ج\or د\or ه\or
و\or ز\or ح\or ط\or ی\or ک\or ل\or م\or ن\or س\or ع\or ف\or ص\or غ\or
ر\or ش\or ت\or ث\
else\@ctrerr\fi}
\makeatother
%-----------------------------------------------------------------------   Body --------------------------------------------------------------
\newcommand{\cchapter}[1]{\chapter[#1]{\centering #1}}
\usepackage{xepersian}

\begin{document}

\pagenumbering{arabic}
\baselineskip = 1cm
\settextfont[Scale=1.4]{B Lotus}
%\addcontentsline{toc}{section}{چکیده}
\tableofcontents
\newpage


\renewcommand\thechapter{       \hspace{5cm}      فصل اول   } 
\chapter{         \hspace{6.5cm}         کلیات تحقیق}

\end{document}