I found a file called template-archive.php inside betheme folder and here is the content of the file. Can you please tell me if it is the correct file to edit. I tried to make if else condition to check if there is any posts, if no, then display there is no results for this search but doesn’t work.
Can you please guide me.

<?php
/**
 * Template Name: Archives
 *
 * @package Betheme
 * @author Muffin Group
 */
get_header();
?>

<div id="Content">
    <div class="content_wrapper clearfix">

        <!-- .sections_group -->
        <div class="sections_group">

            <div class="section">
                <div class="section_wrapper clearfix">

                    <?php
                    if (have_posts()){
                        the_post();
                    }
                   
                    ?>

                    <div class="one-fourth column">
                        <h4><?php _e('Available Pages', 'betheme'); ?></h4>
                        <ul class="list">
                            <?php wp_list_pages('title_li=&depth=-1'); ?>
                        </ul>
                    </div>

                    <div class="one-fourth column">
                        <h4><?php _e('The 20 latest posts', 'betheme'); ?></h4>
                        <ul class="list">
                            <?php
                            $args = array(
                                'post_type' => array('post'),
                                'posts_per_page' => 20
                            );
                            $posts_query = new WP_Query($args);
                           
                             /*if (have_posts()):*/
                            while ($posts_query->have_posts()) : $posts_query->the_post();
                                ?>
                                <li><a>" title="<?php the_title_attribute(); ?>" rel="bookmark"><?php the_title(); ?></a></li>
                            <?php endwhile;
                             /* else :
                        echo wpautop('Sorry, no posts were found');
                    endif;*/
                              
                            wp_reset_query(); ?>
                        </ul>
                    </div>

                    <div class="one-fourth column">
                        <h4><?php _e('Archives by Subject', 'betheme'); ?></h4>
                        <ul class="list">
                            <?php
                            $args = array(
                                'orderby' => 'name',
                                'show_count' => 0,
                                'hide_empty' => 0,
                                'title_li' => '',
                                'taxonomy' => 'category'
                            );
                            wp_list_categories($args);
                            ?>
                        </ul>
                    </div>

                    <div class="one-fourth column">
                        <h4><?php _e('Archives by Month', 'betheme'); ?></h4>
                        <ul class="list">
                            <?php wp_get_archives('type=monthly'); ?>
                        </ul>
                    </div>

                </div>
            </div>

        </div>

    </div>
</div>

<?php get_footer(); ?>

No it’s not the correct one 🙁