Sample code for adding metabox to wordpress

wordpress_metabox.php

/**
 * Adding Metabox for adding a checkbox to hide or unhide the page title
 */
function fay_add_meta_box_for_page_title_display()
{
    add_meta_box( 'fay-meta-box-for-page-title', 'Page Title', 'fay_add_meta_box_for_page_title_display_callback', 'page', 'side', 'high' );
}
add_action( 'add_meta_boxes', 'fay_add_meta_box_for_page_title_display' );

function fay_add_meta_box_for_page_title_display_callback($post){
	//Get the valu of the metbox
	$fay_meta_box_for_page_title_display = get_post_meta( $post->ID, '_fay_page_title_display', true );
	//Checkbox display hepler
	$fay_meta_box_for_page_title_display = $fay_meta_box_for_page_title_display == 'hide' ? 'checked' : '';
	
	wp_nonce_field( 'fay_meta_box_for_page_title_display_nonce', 'fay_meta_box_nonce' );

	echo '<input type="checkbox" id="fay_meta_box_for_page_title_display" name="fay_meta_box_for_page_title_display" value="hide" '.esc_attr($fay_meta_box_for_page_title_display).'/>';
	echo '<label for="fay_meta_box_for_page_title_display">Hide title of this page?</label>';
}

function fay_meta_box_for_page_title_display_nonce ($post_id){
	// Exit if doing an auto save
    if( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;

    // if nonce isn't there, or can't verify it, exit
    if( !isset( $_POST['fay_meta_box_nonce'] ) || !wp_verify_nonce( $_POST['fay_meta_box_nonce'], 'fay_meta_box_for_page_title_display_nonce' ) ) return;

    // if current user can't edit this post, exit
    if( !current_user_can( 'edit_post' ) ) return;

	$data = $_POST['fay_meta_box_for_page_title_display'];
	update_post_meta($post_id, '_fay_page_title_display', $data);
}
add_action('save_post','fay_meta_box_for_page_title_display_nonce');