Since you not provide code for your tree, I use some my tree:
\documentclass[border=3mm]{standalone}\usepackage[edges]{forest}\begin{document}\tikzset{every label/.style={xshift=-4ex, text width=6ex, align=right, inner sep=1pt, font=\footnotesize, text=red}} \begin{forest} for tree={ % style of tree nodes font=\footnotesize, draw, semithick, rounded corners, align = center, inner sep = 2mm, % style of tree (edges, distances, direction) edge = {draw, semithick, -stealth}, parent anchor = east, child anchor = west, grow = south, forked edge, % for forked edge l sep = 12mm, % level distance fork sep = 6mm, % distance from parent to branching point } [Multimedia\\ RSS,label=1 [Multimedia\\ Content,label=1.1] [Multimedia\\ Content,label=1.2.3.4] ] \end{forest}\end{document}