Where to put header

I’m trying to figure out the best way to have html headers throughout my site (eg. <meta name=“robots” content=“noindex, nofollow” />, etc) - most pages have php sessions and ‘includes’, etc which means that I cannot have this at the top - where can I put this information so that I don’t get the dreaded - ‘Warning: Cannot modify header information’ ??

_with thanks

Thanks for the response … I have something like this:

index.php

<?php
session_start();
?>

<?php

include 'html_header.php';

include 'functions.php';

?>

<?php
// get left col
require_once 'left_col.html';
?>

<?php
// get right col
require_once 'right_col.html';
?>

html_header.php

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title><?php echo 'Title'; ?></title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="robots" content="noindex, nofollow" />
</head>

> this seems to be working at the moment and is showing in the page source in the browser …

_thanks

Between the <head> tags of the HTML.

Where do you first print the <html> or DOCTYPE tag? The <head> tag and <meta> tag should be after that.