What I would like is to have the footnote below the bage number at the bottom of the page.
What I did in the example was \item \textbf{Dependency Service\footnote{\url{https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/dependency-service/} }:} permettono di richiamare...
And as you can see the footnote is just below the text, not at the bottom of the page
Take a look at footmisc package and try adding to your preamble
\usepackage[bottom]{footmisc}
This will ensure that footnotes will be placed at the very bottom of your page (but not after the page number, that is printed in the footer of the page). However, is very unlikely that a documentclass will place footnotes below the footer: they would fall outside of the page, if long enough.
Indeed the bottomest part where you can put footnotes is at the bottom of the footer (but that means that you have to dinamically adjust the height of the footer).
\documentclass{...}and ending with\end{document}. – Alessandro Cuttin Mar 11 '20 at 11:18