I am using fonts installed on my computer in LaTeX document as
\documentclass{article}
\usepackage{fontspec}
\newfontfamily\fontx{Ubuntu}
\begin{document}
The default font
{\fontx New font}
The default font
\end{document}
I create the pdf file with lualatex command. How custom fonts are embedded in the pdf document for the sake of compatibility? Readers probably does not have this custom font; does this make a problem in displaying the pdf document?
My knowledge about fonts is very limited. Sorry if it is a basic question. I just want to be sure about the compatibility of my pdf document when using rare fonts, and how to guarantee the document compatibility in different systems.