A simple admin page template.

my-admin-page-template.php

<?php
 /* Plugin Name: My Admin Page Template */
	
	add_action( 'admin_menu', 'my_admin_menu_func' );	
	function my_admin_menu_func() {
		add_options_page( "My Admin Page", "My Admin Page", "manage_options", "my_admin_page_slug", "my_admin_page_func" );
	}
	function my_admin_page_func() {		
		?>
		<div class="wrap">
			<h2>My Admin Page</h2>
			<p>Hello world!</p>				
		</div>
		<?php
	}