understrap/page-templates/fullwidthpage.php

<?php
/**
 * Template Name: Full Width Page
 *
 * Template for displaying a page without sidebar even if a sidebar widget is published
 *
 * @package understrap
 */

 get_header();
?>

<div class="wrapper" id="full-width-page-wrapper">

  <div  id="content" class="container">

    <div id="primary" class="col-md-12 content-area">

      <main id="main" class="site-main" role="main">

        <?php while ( have_posts() ) : the_post(); ?>

          <?php get_template_part( 'loop-templates/content', 'page' ); ?>

          <?php
            // If comments are open or we have at least one comment, load up the comment template
            if ( comments_open() || get_comments_number() ) :

              comments_template();

            endif;
          ?>

        <?php endwhile; // end of the loop. ?>

      </main><!-- #main -->

    </div><!-- #primary -->

  </div><!-- Container end -->

</div><!-- Wrapper end -->

<?php get_footer(); ?>