Hello,

I saw the screenshots you attached and visited your website. The icon on my end is totally different from the icon mentioned in your screenshot.

Screenshot for Clarification: https://ibb.co/c6Nm5LR

Therefore to change it you can try adding the following Custom CSS in the Global Custom CSS area under Theme Settings >> Custom CSS.

.wd-add-btn-replace .add-to-cart-loop::before {
content: "\f019";
font-family: "fontawesome";
}

You can change the icon content according to your needs.

Best Regards.