\definecolor{ublue}{rgb}{0.152,0.250,0.545}
\begin{tikzpicture}
\begin{axis}[  
  width=10cm, height=5cm, 
  xtick={-6,-4,...,6},
  ytick={0,0.5,1},
  xlabel={\small{$x$}},
  ylabel={\small{Softmax($x$)}},
  xlabel style={xshift=4.0cm,yshift=1cm},
  axis y line=middle,
  ylabel style={xshift=-2.4cm,yshift=-0.2cm},
  x axis line style={->},
  axis line style={very thick},
 % ymajorgrids,
  %xmajorgrids,
 axis x line*=bottom,
  xmin=-6.4,
  xmax=6.4,
  ymin=0,
  ymax=1.2]
\addplot[draw=ublue,very thick]{(tanh(x/2) + 1)/2};
\end{axis}
\end{tikzpicture}

%---------------------------------------------------------------------