I have used this code from how-can-i-add-abstract-and-acknowledgement-pages-into-the-table-of-contents to add abstract and acknowledgement. However, I am not able to match the chapter titles with the existing margin format of other chapter titles.

Like shown in the picture!

My code after title page and before introduction chapter is given as;

\pagenumbering{roman}
%\shipout\null
%\stepcounter{page}
\cleardoublepage
\chapter*{Acknowledgement}
\lipsum
\chapter*{Abstract}
\lipsum

%----------------------------------------------------------------------------

\tableofcontents
\listoffigures
\listoftables


Please let me know how to correct the margin in TOC. Thanks in advance!

• Welcome to TeX.SX! Please make your code compilable (if possible), or at least complete it with \documentclass{...}, the required \usepackage's, \begin{document}, and \end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. Aug 29, 2018 at 13:17

I added a bit more of dummy content using the duckuments package. You get the correct alignment if you drop the \numberline{} in the last \addcontentsline argument.

\documentclass[]{report}

\usepackage{duckuments}

\begin{document}
\pagenumbering{roman}
\cleardoublepage
\chapter*{Acknowledgement}
\blindduck
\chapter*{Abstract}