the default search function will only look for posts and pages so you need to add your post_type to the search and can do this in two ways
using the ‘pre_get_posts’ filter to add your post type before the query like this:
function Search_CPT_Filter($query) {
$post_type = $_GET['type'];
if (!$post_type) {
$post_type = array('post','post type name');
}
if ($query->is_search) {
$query->set('post_type', $post_type);
};
return $query;
};
add_filter('pre_get_posts','Search_CPT_Filter');
or, adding the post type to the search form in an hidden filed like this:
<input type="hidden" name="post_type" value="post type name" />
and in both cases just change ‘post type name’ to the name of your post type.