By default, Quarto ignores a newline operator for an author name. So instead of adding an email address in the author variable, you need to customize the title part of the document as follows.

Configure the required information at the top of the jupyter notebook in a markdown format. The title.tex under the template-partials is the tex file that we’ll use for the title box of our document. The title.tex can be replaced with the path of the tex file, for instance ../path_to_title/title.tex.

---
title: "Title of the Document"
subtitle: "Subtitle of the Document"
author: "Your Name"
email: "yourid@email.com"
date: today
date-format: long
output: pdf_document
format:
  pdf:
    template-partials:
      - title.tex
---

Create a title.tex file as follows,

$if(title)$
\title{$title$$if(thanks)$\thanks{$thanks$}$endif$}
$endif$
$if(subtitle)$
$if(beamer)$
$else$
\usepackage{etoolbox}
\makeatletter
\providecommand{\subtitle}[1]{ % add subtitle to \maketitle
\apptocmd{\@title}{\par {\large #1 \par}}{}{}
}
\makeatother
$endif$
\subtitle{$subtitle$}
$endif$
\author{$author$ \\ \small{$email$}}
\date{$date$}

You can further customize the title.tex for any other information you want to include. After the rendering to pdf, the result should look like this.

References

https://quarto.org/docs/authoring/title-blocks.html https://quarto.org/docs/journals/templates.html#template-partials