[Tex/LaTex] How do put a header inside the margins

fancyhdrheader-footermargins

I have to create a document that obeys the following guidelines:

"Margins must be set at a minimum of ¾" (1.87 cm);

Your name must appear outside the set margins of the page, at the top
right corner of every page;"

I have also been informed that I should put other things in the left and centre of the header, in addition to my name.

I'd had planned to do this with fancyhdr, something like:

\documentclass[12pt,letterpaper]{article}

%Set the margins
%I have no idea what headheight=15pt does, but it makes an error go away.
\usepackage[margin=1.87 cm, headheight=15pt]{geometry} 

%Customizing the header
\usepackage{fancyhdr}
\pagestyle{fancyplain}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt} % remove lines as well
\rhead{Canageek}
\chead{B.Sc (Honours Chemistry)}
\lhead{PIN: 314159}
%End footer

\begin{document}
Scholarship application that will give me lots of money.
\end{document}

But this places the header inside the margins, which I think is not what the guidelines are asking for. In specific, the top the the letters are 7 mm from the top of the page, and the bottom of the letters is 1 cm from the top of the page.

Before someone points it out; I am aware that 0.75 inches is not 1.83 cm, someone in the Canadian goverment can't do math.

Best Answer

When I run your code, an error

Package Fancyhdr Warning: \headheight is too small (12.0pt): 
 Make it at least 14.49998pt.
 We now make it that large for the rest of the document.
 This may cause the page layout to be inconsistent, however.

is thrown out.

To correct it, make headheight somewhat larger as in

\usepackage[margin=1.87 cm,headheight=18pt]{geometry}.

I have also adjusted the headsep to reduce some space above.

\documentclass[12pt,letterpaper]{article}

%Set the margins
\usepackage[margin=.75in,showframe,headheight=18pt,headsep=\baselineskip]{geometry}

%Customizing the header
\usepackage{fancyhdr}
\pagestyle{fancyplain}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt} % remove lines as well
\rhead{Canageek}
\chead{B.Sc (Honours Chemistry)}
\lhead{PIN: 314159}
%End footer

\begin{document}
Scholarship application that will give me lots of money.
\end{document}

Here, showframe is used just to show the borders.

Update

From the comments, it is understood that you want to include head and foot inside text area. This can be done by adding includehead and includefoot in the options for geometry.

\documentclass[12pt,letterpaper]{article}

%Set the margins
\usepackage[margin=.75in,showframe,headheight=15pt,headsep=\baselineskip,includehead,includefoot]{geometry}

%Customizing the header
\usepackage{fancyhdr}
\pagestyle{fancyplain}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt} % remove lines as well
\rhead{Canageek}
\chead{B.Sc (Honours Chemistry)}
\lhead{PIN: 314159}
%End footer

\begin{document}
Scholarship application that will give me lots of money.
\end{document}

enter image description here

As a side note, if you do not want margin notes you may add marginparwidth=0pt,marginparsep=0pt, in to the options of geometry.