Add meta to regular page post

functions.php

// register your custom meta box
function my_slider_properties_meta_box() {
    add_meta_box('my_slider_properties', 'Link Format Title URL', 'my_slider_properties', 'page', 'side', 'default');
}
add_action('add_meta_boxes', 'my_slider_properties_meta_box');


// echo your custom meta box
function my_slider_properties() {
    global $post; 

    $my_slider_id = get_post_meta($post->ID, '_my_slider_id', true);

    echo '<p>My slider id</p>';
    echo '<input type="text" name="_my_slider_id" value="' . esc_attr($my_slider_id)  . '" size="40" />';
}


// process your custom meta box while saving
function my_slider_properties_save_meta($post_id, $post) {
    if ( !current_user_can( 'edit_post', $post->ID ))
        return $post->ID;

    $metas['_my_slider_id'] = $_POST['_my_slider_id'];

    foreach ($metas as $key => $value) {
        update_post_meta($post->ID, $key, $value);
    }
}
add_action('save_post', 'my_slider_properties', 1, 2);