The hooks that shape what actually ships in the document head, footer, and body tag. This is where themes and plugins inject meta tags, scripts, and classes without touching template files directly. 2 actions, 3 filters in this category.
wp_headOutputs content in the <head> section
wp_head is the print slot inside document head. Use it for meta tags and inline snippets — not for enqueueing CSS or JS files.
Signature
do_action( 'wp_head' );Example
add_action( 'wp_head', function() {
echo '<meta name="theme-color" content="#0073aa">';
} );Common Use Cases
document_title_partsFilters the parts that build the <title> tag on modern themes
document_title_parts is the modern replacement for wp_title — it works with an array of parts, not a raw string, so you edit pieces instead of parsing text.
Signature
apply_filters( 'document_title_parts', array $title );Example
add_filter( 'document_title_parts', function( $title ) {
if ( is_singular( 'book' ) ) {
$title['title'] .= ' | Book Review';
}
return $title;
} );Common Use Cases
wp_titleFilters the document <title> tag
wp_title is the classic document-title filter. Modern themes should prefer document_title_parts — this hook remains for older title tags.
Signature
apply_filters( 'wp_title', string $title, string $sep, string $seplocation );Example
add_filter( 'wp_title', function( $title, $sep ) {
return $title . $sep . get_bloginfo( 'name' );
}, 10, 2 );Common Use Cases
body_classFilters the CSS classes on <body>
body_class lets CSS target context without extra wrappers. Return the array — do not echo class names.
Signature
apply_filters( 'body_class', string[] $classes, string[] $css_class );Example
add_filter( 'body_class', function( $classes ) {
if ( is_user_logged_in() ) {
$classes[] = 'user-logged-in';
}
return $classes;
} );Common Use Cases
wp_footerFires before </body> closing tag
wp_footer is the last print slot on the front-end. Deferred scripts, analytics, and widgets that must load after content belong here.
Signature
do_action( 'wp_footer' );Example
add_action( 'wp_footer', function() {
echo '<script>console.log("Footer loaded");</script>';
} );Common Use Cases