Look at the manual. It’s typeset as Ti\textit{k}Z
…
You may create a new command if you would like to use it more than one time. If you use xspace
, it takes care of the following space.
\documentclass{article}
\usepackage{xspace}
\newcommand{\TikZ}{Ti\textit{k}Z\xspace}
\begin{document}
\TikZ with a following space and without \TikZ.
\end{document}
For further reading: Drawbacks of xspace
As said in the the comments, there are some other possible definitions:
Ti\emph{k}Z
, which will have an italic k
in upright context and an upright k
in italic context. So the k
is always emphasizes, which may satisfies the source of the name “TikZ ist kein Zeichenprogramm” (TikZ is no drawing software), where the word kein
should be emphasized.
\textup{Ti\textit{k}Z}
will produce the version with upright T
, i
and Z
and italic k
in all cases. This may be preferable, when the original appearance should be kept for the whole document.