Once a customer places an order, you might want to know if such order contains a given product ID. you can use this for tracking purposes, redirect to a custom thank you page or run your custom functions.
Either way, checking this is quite simple thanks to the “woocommerce_thankyou” hook which runs on the order received page. Enjoy!

PHP Snippet: Check if Order Contains Product ID
/** * @snippet WooCommerce: Check if Product ID is in the Order * @how-to Get CustomizeWoo.com FREE * @author Rodolfo Melogli * @compatible WooCommerce 3.8 * @donate $9 https://businessbloomer.com/bloomer-armada/ */ add_action( 'woocommerce_thankyou', 'bbloomer_check_order_product_id' ); function bbloomer_check_order_product_id( $order_id ){ $order = wc_get_order( $order_id ); $items = $order->get_items(); foreach ( $items as $item_id => $item ) { $product_id = $item->get_variation_id() ? $item->get_variation_id() : $item->get_product_id(); if ( $product_id === XYZ ) { // do something } } }