How to translate 'quantity' on Product page.

Please navigate to wp-content/themes/ester/css/woo-style.css file on the server using File manager, edit content: "Quantity" on line 395 in the following piece of code:

.woocommerce div.product form.cart div.quantity::before {
    color: #12252d;
    content: "Quantity";
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.6px;
    text-transform: uppercase;
} 

Then save the file.