This is an adaptation from the Microsoft Word letterhead template released in 2020. It also uses the traditional Berkeley fonts.
\begin
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%%
% UC Berkeley Modern Letterhead Informal Color Version
% LaTeX Template
% April 2020
%
% Adapted from Microsoft Word template
% https://brand.berkeley.edu/stationery/
% by Chris Hoofnagle https://hoofnagle.berkeley.edu
%
% License: faculty and staff of the University of California are free to use this template
%%
\documentclass[12pt,letterpaper]{letter} %this controls the paper style and font size
\usepackage{graphicx} % necessary for logos
\usepackage{lipsum} %you can delete this
\usepackage{geometry} % so that page 2> have 1" margins
\usepackage{fancyhdr} % for fancy headers
\usepackage{xcolor}
\usepackage{lastpage}
\pagestyle{fancy}
\renewcommand{\headrulewidth}{0pt}
\fancyhead{} % footer for pages 2 on
\lfoot{\footnotesize {\textit{Letter from \Who{} regarding ...}}} % Left footer
\cfoot{} % Change for center footer
\rfoot{\footnotesize Page \thepage\ of \pageref{LastPage}} % Right footer page #s
\renewcommand{\footrulewidth}{0pt}
%this gives you Berkeley fonts
\usepackage{fontspec}
\setmainfont{UCBerkeleyOS.otf}[
BoldFont = UCBerkeleyOSBold.otf ,
ItalicFont = UCBerkeleyOSItalic.otf ,
BoldItalicFont = UCBerkeleyOSBoldItalic.otf ]
%Sender Information -- Edit this to fill in the header
\def\Who{Firstname Lastname} % Fill in your name here
\def\Title{Title} % Your title
\def\Where{Department} % Your department/institution
\def\Address{Address} % Your address
\def\CityZip{Berkeley CA, 94720} % Your city, zip code, country, etc
\def\Email{E-mail: username@berkeley.edu} % Your email address
\def\TEL{Phone: (510) 642--0000} % Your phone number
\def\TELM{Mobile: (510) XXX--XXXX} % Do you dare put your mobile here? How about a fax?
\def\URL{https://*.berkeley.edu} % Your URL
\topmargin=-1.1in % Moves the top margin; here it is a negative value to move the text up
\textheight=9.5in % Total text height for this page
\oddsidemargin=-10pt % Left margin; widened here with a negative value
\textwidth=7in % Text width
\let\raggedleft\raggedright % Makes the date appear on the left
\begin{document}
\begin{letter}{Recipient name \\ Street\\ City\\ Country \\ \medskip Re:} %put the recipient information here and maybe a reference line
% This controls the header. It places the Berkeley wordmark on the left, two columns with name and address in the center, and the seal on the right. You can adjust the textwidth allocations to balance out the columns.
\begin{center}
\begin{picture}(1000,1)
\put(0,-50){\includegraphics[width=\textwidth]{casualheaderrawtrim.png}}
\textcolor{white}{
\put(190,12){\textbf{\footnotesize Your Name}}
\put(190,2){\footnotesize Your Title}
\put(190,-8){\footnotesize Department Name}
\put(320,12){\footnotesize 2190 Any Street}
\put(320,2){\footnotesize 510--643--0000 phone}
\put(320,-8){\footnotesize 510--643--0000 fax or mobile}
\put(320,-18){\footnotesize Your email@berkeley.edu}
\put(320,-28){\footnotesize yourURL.berkeley.edu}}
\end{picture}
\end{center}
\vspace{16mm}
\opening{Dear Professor Recipient Name,}
Replace these contents with your own!
\lipsum[1-3] %erase this to remove placeholder text
\newpage % use this command to break to page 2. It's included here so that the margins will be different on pages 2>
\newgeometry{top=1in,bottom=1in,right=1in,left=1in} %page dimensions for page 2>
\textbf{Feel free to use}
\begin{itemize}
\item bullets
\end{itemize}
\begin{enumerate}
\item numbered lists
\item numbered lists interrupted by bullets
\begin{itemize}
\item A bullet between numbers
\end{itemize}
\item Yes, anything is possible
\end{enumerate}
\textit{The quote command:}
\begin{quotation}
Hello my friend, we've been waiting for you for a long time \\
We have reason to believe that your soul is just like ours \\
Did you ever get the feeling you were just a little different? \\
Well, here’s our web page, you've finally found a home
\end{quotation}
\textbf{\textit{The verse command:}}
\begin{verse}
As for me, I am light and joyous! I discover in men dazzling perspectives, with Paradises in the clouds and distant felicities. I pour into their souls the eternal insanities, projects of happiness, plans for the future, dreams of glory, and oaths of love, as well as virtuous resolutions. I drive them on perilous voyages and on mighty enterprises. I have carved with my claws the marvels of architecture. It is I that hung the little bells on the tomb of Porsenna, and surrounded with a wall of Corinthian brass the quays of the Atlantides.
I seek fresh perfumes, larger flowers, pleasures hitherto unknown. If anywhere I find a man whose soul reposes in wisdom, I fall upon him and strangle him.
\end{verse}
\closing{Sincerely,}
% \includegraphics[]{} You can put an image of your signature here.
\Who{}
\ps{P.S. Fiat Lux}
\cc{Carbon Copy 1\\Carbon Copy 2}
\encl{Memorandum} %for enclosures
\end{letter}
\end{document}