The TikZ-based method can be wrapped into a macro as shown here:
https://tex.stackexchange.com/a/311031 .
The given macro allows the specification of an anchor point of the box and uses fractions of the page dimensions for accurate positioning. There is no need for setting margins or additional calculations.

Your example:
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[]{xcolor}
\usepackage{tikz}
\usetikzlibrary{calc}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% absolute positioning of typeset material
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\newcommand{\placetextbox}[4][center]{%
% [#1]: box anchor: center (default) |
% south west | west | north west | north |
% north east | east | south east | south |
% mid west | mid | mid east |
% base west | base | base east
% #2: horizontal position (fraction of page width)
% #3: vertical position (fraction of page height)
% #4: content
%
\tikz[remember picture,overlay,x=\paperwidth,y=\paperheight]{%
\node[anchor=#1,inner sep=0pt]
at ($(current page.south west)+(#2,#3)$) {#4};
}%
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\placetextbox[north]{0.5}{1.0}{%
\colorbox{pink}{%
\begin{minipage}[t][0.3\textwidth][b]{0.3\textwidth}
\sffamily
\resizebox{\linewidth}{!}{\textcolor{white}{\Huge \textbf{KATIE}}}\\[0.5ex]
\resizebox{\linewidth}{!}{\textcolor{white}{\Huge \textbf{SMALLS}}}
\end{minipage}}%
}
\end{document}
\documentclass{article}) for a CV ? A lot of packages are specially designed for CV ... – Jérôme Dequeker Jun 28 '16 at 07:57\colorbox, let's say, outside the margins – Andrea Jun 28 '16 at 08:09\documentclass[demo]{beamer}, and the solution withtikzseems even more complicated – Andrea Jun 28 '16 at 08:22beamerclass before and the related controls. It works. Now remain how to allign the two words. – Andrea Jun 28 '16 at 08:34