Actually i have created a custom theme.

<?php
/**
 * Template Name: News Search Page
 *
 */

get_header();

?>

    <div class="main_content">
        <div class="category_header">
            <div class="row">
                <div class="col-sm-12">
                    <div class="custom-breadcrumb">
                        <h1>News Digest</h1>
                        <?php
                        schema_breadcrumb();
                        ?>
                    </div>
                </div>
            </div>
        </div>
    </div>

    <div class="container container-most">

        <div class="row">

            <?php
            if ( have_posts() ) :
                // Start the loop.
                while ( have_posts() ) : the_post();
                    get_template_part( 'content', '' );

                    // End the loop.
                endwhile;

                // Previous/next page navigation.
                global $wp_query;

                $big = 999999999; // need an unlikely integer

                $pages = paginate_links( array(
                    'base'          => get_pagenum_link(1) . '%_%',
                    'format'        => '/?paged=%#%', // ?page=%#% : %#% is replaced by the page number
                    'prev_next'          => true,
                    'prev_text'          => __('<span aria-hidden="true">&laquo;</span>'),
                    'next_text'          => __('<span aria-hidden="true">&raquo;</span>'),
                    'current' => max( 1, get_query_var('paged') ),
                    'total' => $wp_query->max_num_pages,
                    'type'  => 'array',
                ) );
                if( is_array( $pages ) ) :
                    $paged = ( get_query_var('paged') == 0 ) ? 1 : get_query_var('paged');
                    echo '<div class="col-sm-12"><nav aria-label="Page navigation" style="text-align: center;"><ul class="pagination">';
                    foreach ( $pages as $page ) {
                        echo "<li>$page</li>";
                    }
                    echo '</ul></nav></div>';
                endif;
            // If no content, include the "No posts found" template.
            else :
                get_template_part( 'content', 'none' );
            endif;
            ?>

        </div>

    </div>

<?php
get_footer();
?>

search page showing the rss feed link like below
https://example.com/search/Barack+Obama/feed/rss2/
How do I change it like below or Is it possible to do replace the feed link?
https://example.com/news/Barack+Obama/feed/rss2/

Now in search page the rss feed link URL still showing the “search” in url

Are you saying you have an RSS feed just for the search page? If so, is that generated from a plugin? Which?

search page showing the rss feed url like below
https://example.com/search/Barack+Obama/feed/rss2/
How do I change it like below or Is it possible to do replace the feed url for the search page as below?
https://example.com/news/Barack+Obama/feed/rss2/