Add ACF fields to search results page WordPress

I have a file named search.php, where all the search results are added. The search form is located on the homepage. The problem is, I have no special page for the search results, but I want to add ACF fields to this page. I have searched in the dropdown menu 'location' in the ACF plugin, but I can't find the search.php file to add groups to. I am sorry if my explaination is a bit vague, but I don't know how to explain this exactly.

Summary, I want to add ACF fields to my search.php search results page.

Terminology: ACF stand for the Advanced Custom Fields plugin in WordPress.

You can also do it using plugin but use below code to avoide plugin.

You need to add this code in you function.php file

<?php
/**
 * [list_searcheable_acf list all the custom fields we want to include in our search query]
 * @return [array] [list of custom fields]
 */
function list_searcheable_acf(){
  $list_searcheable_acf = array("title", "sub_title", "excerpt_short", "excerpt_long", "xyz", "myACF");
  return $list_searcheable_acf;
}
/**
 * [advanced_custom_search search that encompasses ACF/advanced custom fields and taxonomies and split expression before request]
 * @param  [query-part/string]      $where    [the initial "where" part of the search query]
 * @param  [object]                 $wp_query []
 * @return [query-part/string]      $where    [the "where" part of the search query as we customized]
 * see https://vzurczak.wordpress.com/2013/06/15/extend-the-default-wordpress-search/
 * credits to Vincent Zurczak for the base query structure/spliting tags section
 */
function advanced_custom_search( $where, &$wp_query ) {
    global $wpdb;

    if ( empty( $where ))
        return $where;

    // get search expression
    $terms = $wp_query->query_vars[ 's' ];

    // explode search expression to get search terms
    $exploded = explode( ' ', $terms );
    if( $exploded === FALSE || count( $exploded ) == 0 )
        $exploded = array( 0 => $terms );

    // reset search in order to rebuilt it as we whish
    $where = '';

    // get searcheable_acf, a list of advanced custom fields you want to search content in
    $list_searcheable_acf = list_searcheable_acf();
    foreach( $exploded as $tag ) :
        $where .= " 
          AND (
            (wp_posts.post_title LIKE '%$tag%')
            OR (wp_posts.post_content LIKE '%$tag%')
            OR EXISTS (
              SELECT * FROM wp_postmeta
                  WHERE post_id = wp_posts.ID
                    AND (";
        foreach ($list_searcheable_acf as $searcheable_acf) :
          if ($searcheable_acf == $list_searcheable_acf[0]):
            $where .= " (meta_key LIKE '%" . $searcheable_acf . "%' AND meta_value LIKE '%$tag%') ";
          else :
            $where .= " OR (meta_key LIKE '%" . $searcheable_acf . "%' AND meta_value LIKE '%$tag%') ";
          endif;
        endforeach;
            $where .= ")
            )
            OR EXISTS (
              SELECT * FROM wp_comments
              WHERE comment_post_ID = wp_posts.ID
                AND comment_content LIKE '%$tag%'
            )
            OR EXISTS (
              SELECT * FROM wp_terms
              INNER JOIN wp_term_taxonomy
                ON wp_term_taxonomy.term_id = wp_terms.term_id
              INNER JOIN wp_term_relationships
                ON wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id
              WHERE (
                taxonomy = 'post_tag'
                    OR taxonomy = 'category'                
                    OR taxonomy = 'myCustomTax'
                )
                AND object_id = wp_posts.ID
                AND wp_terms.name LIKE '%$tag%'
            )
        )";
    endforeach;
    return $where;
}

add_filter( 'posts_search', 'advanced_custom_search', 500, 2 );

for reference - https://gist.github.com/charleslouis/5924863

Try This solution if first is not working.

https://support.advancedcustomfields.com/forums/topic/making-customfields-searchable/