WooCommerce does allow you to limit the quantity of a single product. But there’s no option to achieve the same for all products at once.
You can limit the quantity to 1 for all WooCommerc products by using the ‘woocommerce_is_sold_individually’ filter.
php
/**
* Limit Product Quantity to 1 for All WooCommerce Products
*/
function maverick_limit_product_quantity($return, $product)
{
return true;
}
add_filter('woocommerce_is_sold_individually', 'maverick_limit_product_quantity', 10, 2);