If you are making a print only document using Shadows CSS make sure the content is inside the "main" tags. 

... header stuff ...

<p>This will not print.</p>

<main>
	<p>
		Only stuff in the "main" tag will print.
	</p>
</main>

... footer stuff ...

Suggestion: If you need a print only document, use bootstrap 5 to set up a simple template that uses a CSS framework designed for both web and print.