Hello,

By default, YITH Wishlist plugin didn’t have “Add to wishlist” button on the shop page product grid (http://prntscr.com/p4ky3e).

You can check how it works in default theme on official YITH Wishlist demo site: https://plugins.yithemes.com/yith-woocommerce-wishlist/shop/

If you still want the icon on the product grid, you will have to use our built-in Wish-list.

Regards