I created this function in functions.php:

function wpbsearchform( $form ) {

 $form = 
    '<form role="search" method="get" class="searchform" action="' . home_url( '/' ) . 
 '" >
  <div><label class="screen-reader-text" for="s">' . __('Search for:') . '</label>
  <input type="text" value="' . get_search_query() . '" name="s" id="s" />
  <input type="submit" id="searchsubmit" value="'. esc_attr__('Search') .'" />
  </div>
 </form>';

  return $form;
 }

 add_shortcode('wpbsearch', 'wpbsearchform');

The result is redirected to a page with this querty string, ?s=hello. I want to modify the search results template but I don't know where it is located. can any one help me