I am trying to add my product to cart. I have created product type bookable_product. So when I executed below code function add_bookable_product_to_cart() { if (! is_admin()) { $product_id = 38; // Your bookable product ID $product_cart_id = WC()->cart->generate_cart_id($product_id); if (! WC()->cart->find_product_in_cart($product_cart_id)) { // Add the bookable product to the cart $added = WC()->cart->add_to_cart($product_id); if (!$added) { // Handle failure to add, maybe log or display an error error_log('Could not add product to cart: ' . $product_id); } } } } add_action("wp", "add_bookable_product_to_cart", 10); As per this doc I have used WooCommerce for only product management purpose all fields I have created my self. So in default product I have not added any data of WC.