[Tex/LaTex] change the font of chapter title and section title


I am trying to change the font and format of heading using titlesec package. However it gives me the following error.

Missing { inserted \tableofcontents <br>
Missing { inserted \chapter{Introduction} 

The code:

\documentclass[10pt, letterpaper]{report}

        {\normalfont\Large\centering\uppercase}{\chaptertitlename\ \thechapter}{0pt}{\Large}



Some text.


Best Answer

\uppercase requires a parameter, which is not supported in this argument of \titleformat. But it's supported within another argument, that's why this works:

        {\normalfont\Large\centering}{\chaptertitlename\ \thechapter}{0pt}{\Large\uppercase}

The very last command in the last mandatory argument here can take an argument, which is the title text.