Select2 is a jQuery-based replacement for select boxes. In WS Form, you can add it to any Select or Price Select field in your form in WordPress.
Select2 supports searching, AJAX, and infinite scrolling of results. If your select field has a lot of options, you can enable AJAX to help improve performance.
You can enable Select2 in the field settings, or add it manually to a Select or Price Select field on your website.