To add vertical space between paragraphs we can use \vspace{12pt} or \\[12pt]. But why does the latter adds more space when it is followed by an empty line?
\documentclass{article}
\begin{document}
My first para.\vspace{12pt}
My second para.\\[12pt]
My third para.
\end{document}
\\is absolutely wrong. See Best choice between using\\or leaving space after each paragraph to end the paragraph. And you should leave a blank line before\vspace. – barbara beeton Apr 26 '20 at 02:03\\[...]is defined as\vspace{...}\newline, and\newline\paradds an extra line.. – John Kormylo Apr 26 '20 at 02:33