Register nav menu in wordpress

Add in functions.php


<?php
add_action( 'after_setup_theme', 'register_my_menu' );
function register_my_menu() {
  register_nav_menu( 'test', __( 'Test Menu', 'theme-slug' ) );
}
?>

Create page templates in wordpress.

<?php

/**
 * Template Name: PHP-AJAX-HTML
 *
 */

get_header(); ?>

<div id="primary" class="content-area">
<main id="main" class="site-main" role="main">

Yes It's working fine.

</main><!-- .site-main -->
</div><!-- .content-area -->

<?php get_footer(); ?>