LaTeX Forum

\documentclass[tikz, border=5pt]{standalone}
\usetikzlibrary{trees,arrows.meta}

\tikzset{font=\sffamily}

\begin{document}
\begin{tikzpicture}[
	edge from parent fork down,
	level distance=2.5cm,
	sibling distance=2.5cm,
	thick,
	box/.style={
		draw,
		minimum width=1.2cm,
		minimum height=\pgfkeysvalueof{/pgf/minimum width}/2,
		rounded corners
	},
	every child node/.style={box},
	labelbelownode/.style={
		label={[anchor=north west]below:#1}
	},
	labelfont/.style={font=\sffamily\footnotesize},
	every label/.style={labelfont},
	edge from parent/.style={
		draw,
		-Triangle,
		labelfont,
		pos=.7
	}
]
\node [box, labelbelownode=AB] {A2}
	child {
		node {A3}
		edge from parent
			node [left] {excluded}
	}
	child {node [labelbelownode=DE] {A4}
		child {
			node {A5}
			edge from parent
				node [left] {excluded}
		}
		child {
			node {A6}
			edge from parent
				node [right] {included}
		}
		edge from parent
			node [right] {included}
	}
;
\end{tikzpicture}
\end{document}

% A simple Tree
% Author: Stefan Kottwitz
% https://www.packtpub.com/hardware-and-creative/latex-cookbook
\documentclass[border=10pt]{standalone} 
%%%<
\usepackage{verbatim}
%%%>


\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[sibling distance=10em,
  every node/.style = {shape=rectangle, rounded corners,
    draw, align=center,
    top color=white, bottom color=white}]]
  \node {A2}
    child { node {A3} }
    child { node {A4} }
      child { node {A5}
        child { node {A6} }      
      child { node {first left,\\centered,\\last right} } };
\end{tikzpicture}
\end{document}