seacrh filter posts only

wordpress-limit-search-resluts-post-type.php

// Search filter returning posts only, not pages

function sd_limit_search_results_post_type( $query ) {
  if ( $query->is_search ) {
    $query->set( 'post_type', 'post' );
  }
  return $query;
}
add_filter( 'pre_get_posts', 'sd_limit_search_results_post_type' );