\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\begin{document}
\begin{tikzpicture}[remember picture]
\node at (0,0) {This letter is \subnode{Ti}{T}};
\node at (3,1.5) {\subnode{Tf}{T}his is a Cat};
\draw[->, shorten <=1pt] (Ti) -- (Tf);
\node at (0,2) {This letter is \subnode{Ci}{C}};
\node at (3,3.5) {This is a \subnode{Cf}{C}at};
\draw[->] (Ci) -- (Cf);
\node at (0,4) {This letter is \subnode{ai}{a}};
\node at (3,5.5) {This is \subnode{af}{a} Cat};
\draw[->] (ai) -- (af);
\end{tikzpicture}
\end{document}