Search engine not working

You have to create a php file named search.php. Inside that file, write the code below:

<?php get_header(); ?>

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

    <article class="entry">
        <header class="entry-title">
            <h2><a href="https://wordpress.stackexchange.com/questions/172942/<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>            
        </header>
        <div class="entry-content">
            <?php the_content( 'Read More' ); ?>
        </div>
    </article>

<?php endwhile; ?>

<?php endif; ?>

<?php get_footer(); ?>