Hello,

The Wishlist icon under the Theme already shows on the Products like this for the Archive pages: https://snipboard.io/KIoQP9.jpg

On Single Product page like this: https://snipboard.io/cY3euq.jpg

Under the Header, it previews like this: https://snipboard.io/ZacBvw.jpg

Other than these, where specifically do you want to add a Wishlist Icon or button on your Site? Could you please elaborate it with some useful Screenshots and Page URLs for our better understanding.

Best Regards