add-to-cart.php

<?php
echo apply_filters(
    'woocommerce_loop_add_to_cart_link', // WPCS: XSS ok.
    sprintf(
        '<a rel="nofollow" href="%s" data-quantity="%s" data-product_id="%s" data-product_sku="%s" class="%s" %s>%s</a>',
        esc_url( $product->add_to_cart_url() ),
        esc_attr( isset( $args['quantity'] ) ? $args['quantity'] : 1 ),
        esc_attr( $product->get_id() ),
        esc_attr( $product->get_sku() ),
        esc_attr( isset( $args['class'] ) ? $args['class'] : 'button' ),
        isset( $args['attributes'] ) ? wc_implode_html_attributes( $args['attributes'] ) : '',
        esc_html( $product->add_to_cart_text() )
    ),
    $product,
    $args
);

functions.php

<?php 

function wvs_noo_organici_theme_support() {
	add_action( 'woocommerce_after_shop_loop_item_title', 'wvs_pro_archive_variation_template', 10 );
}

add_action( 'init', 'wvs_noo_organici_theme_support' );

style.css

a.add_to_cart_button:before {
    font-family: 'FontAwesome';
    content: '';
    content: "\f07a";
    padding-right: 10px;
}

woocommerce_class.php

<?php wc_product_class( ' ', $product ); ?>