Hi,
Here you can just add this CSS on your Customizer -> Additional CSS section
.woocommerce ul.products li.product, .woocommerce-page ul.products li.product {
box-shadow: none !important;
background: none !important;
}
If you just want to remove box shadow use.
.woocommerce ul.products li.product, .woocommerce-page ul.products li.product {
box-shadow: none !important;
}
Hope this will solve your problem.
Regards
Support Team