Complete PHP novice here, so apologies for asking what may be a really basic question. Currently I only use PHP for include files, to make site maintenance easier. Nothing database driven. Just this kind of thing...
Code PHP:
<?php include "../includes/masthead.php"; ?>

However I've only ever used includes on elements within the <body> tag. Is it possible (and normal practice) to include elements of the <head> too, or at least those that stay the same or similar from page to page? Things like...

the doctype declararation
<link rel="icon" type="image/x-icon" href="/favicon.ico" />
<meta name="description" content="" />
<meta name="keywords" content="" />

And if so, is the way of 'calling' them the same as in the body tag?
Code PHP:
<?php include "../includes/doctype.php"; ?>
<?php include "../includes/faviconlink.php"; ?>
<?php include "../includes/meta-desc-1c.php"; ?>
<?php include "../includes/meta-keywords-1c.php"; ?>