The Content of the document overlying the header content

Question

\documentclass{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[a4paper, total={6in, 9in}]{geometry}
\usepackage{fancyhdr,stix,graphicx,framed,amsmath,amssymb,blindtext}


\pagestyle{fancy}
\fancyhf{}
\rhead{Right Header Content}
\lhead{\includegraphics[scale=.15]{logo-tv-logo.png}
}
\rfoot{Page \thepage}
\newcommand\fillin[1][3cm]{\makebox[#1]{\dotfill}}

\begin{document}

\blindtext
\end{document}

Answer 1

The package fancyhdr doesn't adjust the margins of the page to the content of the header line, but you have to adjust that manually.

Compiling this code:

\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage{fancyhdr}
\usepackage{blindtext}

\pagestyle{fancy}
\lhead{\includegraphics[scale=.15]{logo}}

\begin{document}

\blindtext
\end{document}

I get in the log file a warning:

Package Fancyhdr Warning: \headheight is too small (12.0pt):
Make it at least 103.60004pt.

So that is what you do: You increase the the height of the head to 104pt (or so) in the header of your code using

\setlength\headheight{104pt}

Of course, you have to adjust this length to the actual image you are using (i.e. according to the warning in your log file).