Cfrgtkky

I'am using memoir.
With these basic settings:

makechapterstyle{chappell2}{%

setlength{beforechapskip}{-15pt}

renewcommand*{chapnamefont}{large}



renewcommand*{printchapternum}{chapnumfont Large thechapter }

renewcommand*{chaptitlefont}{Largebfseries}

renewcommand*{printchaptertitle}[1]{%

%vskiponelineskip 

chaptitlefont ##1}}



makechapterstyle{mystyle}{%

    chapterstyle{default}

    renewcommand{printchaptername}{}

    renewcommand{chapternamenum}{}

    renewcommand{chapnumfont}{normalfontbfseries}

    renewcommand{printchapternum}{}%chapnumfont thechapterspace}

    renewcommand{afterchapternum}{}

    renewcommand*{printchapternum}{%

    @hangfrom{chapnumfont thechapterquad}}%

}

%nouppercaseheads



chapterstyle{chappell2}

renewcommandthechapter{Capitolo arabic{chapter}}

renewcommandthesection{arabic{section}}

renewcommandthesubsection{thesection.arabic{subsection}}

renewcommandthesubsubsection{thesubsectionarabic{subsubsection}}

I get this:

I would like to print in the heading only "Capitolo 2".
How can I do it?
Sorry, but I'am not an expert in latex...

You did not provide a compilable example which must start from documentclass... through to end{document}. What you did provide when I added the necessary code did not produce what you showed in your graphic.

I have done my best and I think that this is what might suit you.

documentclass{memoir}

usepackage{lipsum}



renewcommand{chaptername}{Capitolo}  % change chapter name

renewcommand{chapterrefname}{Capitolo} % change chapter reference name  

makechapterstyle{chappell2}{%

setlength{beforechapskip}{-15pt}

%renewcommand*{chapnamefont}{large}

renewcommand*{chapnamefont}{Largebfseries} % to match the chapter number



renewcommand*{printchapternum}{chapnumfont Large thechapter }

renewcommand*{chaptitlefont}{Largebfseries}

renewcommand*{printchaptertitle}[1]{%

%vskiponelineskip 

chaptitlefont ##1}}



%nouppercaseheads



chapterstyle{chappell2}

%renewcommandthechapter{Capitolo arabic{chapter}}

renewcommandthesection{arabic{section}}

renewcommandthesubsection{thesection.arabic{subsection}}

renewcommandthesubsubsection{thesubsectionarabic{subsubsection}}



begin{document}



frontmatter

tableofcontents

mainmatter

chapter{INFORMAZIONI}

lipsum[1]

section{First section}

lipsum

chapter{ANOTHER}

lipsum[2]

end{document}

You defined a mystyle chapterstyle but did not use it. Why?