Реализуем различные заголовки Title, H1 и мета-описание в WordPress без плагинов

// Кастомный Title
add_filter('document_title_parts', 'custom_document_title');
function custom_document_title($title) {
    if (is_singular()) {
        $custom_title = get_post_meta(get_the_ID(), 'custom_title', true);
        if (!empty($custom_title)) {
            $title['title'] = $custom_title;
        }
    }
    return $title;
}

// Кастомный H1 (вставьте в шаблон, например single.php)
function custom_h1_output() {
    $custom_h1 = get_post_meta(get_the_ID(), 'custom_h1', true);
    $output = !empty($custom_h1) ? $custom_h1 : get_the_title();
    return '<h1>' . esc_html($output) . '</h1>';
}

// Мета-описание
add_action('wp_head', 'custom_meta_description');
function custom_meta_description() {
    if (is_singular()) {
        $custom_desc = get_post_meta(get_the_ID(), 'custom_description', true);
        
        if (empty($custom_desc)) {
            $content = get_the_content();
            $content = wp_strip_all_tags($content);
            $content = preg_replace('/\s+/', ' ', $content);
            
            if (mb_strlen($content) > 160) {
                $custom_desc = mb_substr($content, 0, 160);
                $last_space = mb_strrpos($custom_desc, ' ');
                $custom_desc = mb_substr($custom_desc, 0, $last_space) . '...';
            } else {
                $custom_desc = $content;
            }
        }
        
        echo '<meta name="description" content="' . esc_attr($custom_desc) . '">';
    }
}