\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{positioning,arrows.meta}
\tikzset{
box/.style={
rectangle,
minimum width=15mm
,minimum height=1cm,
draw,
line width=2pt,
cyan!50!blue,
text=black},
arr/.style={
line width=2pt,
cyan!50!blue,
-Stealth}
}
\begin{document}
\begin{tikzpicture}
\node[box] (root) {ROOT};
\node[box,below left = of root] (child one) {ONE};
\node[box,below = of root] (child two) {TWO};
\node[box,below right = of root] (child three) {THREE};
\draw[arr] (root) --++ (0,-.85) -| (child one);
\draw[arr] (root) -- (child two);
\draw[arr] (root) --++ (0,-.85) -| (child three);
\end{tikzpicture}
\end{document}