By default, WordPress will not give your posts and pages any meta keywords or description. Though meta keywords are probably obsolete, here’s a handy trick for how to use post tags as meta keywords in WordPress.
Just go to Appearance > Editor and add this code to your header.php file:
<!--BEGIN Uses post tags as meta keywords-->
<?php
if (!is_page()) {
$postTags = get_the_tags();
$tagNames = array();
foreach($postTags as $tag) {
$tagNames[] = $tag->name;
}
?>
<meta name="keywords" content="<?php echo implode($tagNames,","); ?>" />
<?php
}
?>
<!--END Uses post tags as meta keywords-->
And create a custom field called custom_description to use as the meta description, which is still displayed in search results under the page title:
<!--BEGIN Checks for custom field to determine meta description, otherwise site tagline is used-->
<meta name="description" content="<?php
$thisPost = $post -> ID;
if (get_post_meta($thisPost, custom_description, true) != "") {
echo (get_post_meta($thisPost, custom_description, true));
} else {
bloginfo('description');
}
?>" />
<!--END Checks for custom field to determine meta description, otherwise site tagline is used-->