What am I doing wrong ? Changing the value next to pos= doesn't move the node...
\documentclass[border=2pt]{standalone}
\usepackage[utf8]{inputenc}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}[scale=2]
\def\LimiTrace{6}
\draw[blue,samples=100,line width=2pt] plot [domain=0:\LimiTrace] (\x,{(1-exp(-\x))*3}) node[pos=0.9] {$s(t)$};
\end{tikzpicture}
\end{document}

s(t)? right of end of figure? than try withnode[right] {$s(t)$}. – Zarko Jul 23 '19 at 11:47pos=0.5likemidwaywith more possibilities, but you can't. what a shame. – LMT-PhD Jul 23 '19 at 12:02plots(and id does withdecorations.markings) but since you are loadingpgfplotsyou could just do\documentclass[border=2pt]{standalone} \usepackage{pgfplots} \pgfplotsset{compat=1.16} \begin{document} \begin{tikzpicture} \begin{axis} \def\LimiTrace{6} \addplot[blue,samples=100,line width=2pt,domain=0:\LimiTrace] {(1-exp(-x))*3} node[pos=0.9,below] {$s(t)$}; \end{axis} \end{tikzpicture} \end{document}where this syntax works. – Jul 23 '19 at 12:051.14also works. (I always add the compatibility mode in order to make the result reproducable.) – Jul 23 '19 at 12:39