There's any way on LaTeX to make a note between lines of the normal text? Exactly like this:

In this case, the note/var ("r") over the "t" character...
Using \overset with amsmath package in math mode is a possible solution.
\documentclass[]{article}
\usepackage{amsmath}
\newcommand{\os}[2]{${\overset{\text{#1}}{\text{#2}}}$}
\begin{document}
Vat. has \textit{an\os{r}{t}e:}
Vat. has an\os{r}{t}e:
\end{document}
stackengine-package
– Florian
Jan 24 '20 at 13:38
\undersetand\oversetcommands are your friends: https://tex.stackexchange.com/a/39230/31034 – Dec 30 '19 at 14:05