Disable exceptional behavior of the first page in letter

Question

I use the following code for my letter:

\documentclass[a4paper, 11pt]{letter}

\usepackage{fontspec}
\usepackage{fancyhdr}


\newcommand{\DocumentTitle}{Motivation Letter}
\newcommand{\Author}{Johm Smith}

\setmainfont{Times New Roman}

\usepackage[hmargin=1in,vmargin=1in]{geometry}
\linespread{1.3}

\pagestyle{fancy}
\fancyhf{} % clear all header and footers
\fancyhead[L]{\DocumentTitle \\ \Author}
\fancyhead[R]{\thepage}
\fancyfoot[L]{\DocumentTitle \\ \Author}
\fancyfoot[R]{\thepage}

\renewcommand{\headrulewidth}{0.4pt}
\renewcommand{\footrulewidth}{0.4pt}
\thispagestyle{fancy}

\begin{document}

\begin{letter}{ }

\signature{\Author}

\opening{To Whom It May Concern,}
\closing{Respectfully,}

\end{letter}

\end{document}

But there is no these header and footer on the first page. How to change this behavior?

Answer 1

In the letter document class, \opening issues \thispagestyle{firstpage}, where \ps@firstpage is defined in letter.cls for the first page of a letter. To apply the same header/footer to this page, you can \let the firstpage style to be fancy, using

\let\ps@firstpage\ps@fancy

A complete example:

\documentclass[a4paper, 11pt]{letter}

\usepackage{fontspec}
\usepackage{fancyhdr}


\newcommand{\DocumentTitle}{Motivation Letter}
\newcommand{\Author}{Johm Smith}

%\setmainfont{Times New Roman}

\usepackage[hmargin=1in,vmargin=1in]{geometry}
\linespread{1.3}

\pagestyle{fancy}
\fancyhf{} % clear all header and footers
\fancyhead[L]{\DocumentTitle \\ \Author}
\fancyhead[R]{\thepage}
\fancyfoot[L]{\DocumentTitle \\ \Author}
\fancyfoot[R]{\thepage}

\renewcommand{\headrulewidth}{0.4pt}
\renewcommand{\footrulewidth}{0.4pt}

\makeatletter
\let\ps@firstpage\ps@fancy
\makeatother

\begin{document}

\begin{letter}{ }
\signature{\Author}

\opening{To Whom It May Concern,}
\closing{Respectfully,}

\end{letter}
\end{document} 

I commented out the line \setmainfont{Times New Roman} in my example code, since I don't have this font in my system.