Add Toggle to Container Headings

Hi,

I noticed on the WOOF Woocommerce Product Filters demo site (https://demo.products-filter.com) that there is a toggle icon to the right of the filter container headings. How can I enable this functionality on my site? I would also like the toggle to be closed by default so that users must open it to see the hidden checkboxes underneath the filter heading.

The page I need help with: [log in to see the link]