WooCommerce | Add custom text to the emails based on the status of the order and if a product ID is in the order

woocommerce-custom-order-email-note-for-product.php

<?php

/**************
DIFFERENT MESSAGES FOR DIFFERENT PRODUCTS
****************/
 
//hook our function to the new order email
add_action('woocommerce_email_order_details', 'email_order_details_products', 1, 4);
 
function email_order_details_products($order, $admin, $plain, $email) {
	// getting the status of the current order
	$status = $order->get_status();
  
	// checking if it's the order status we want (note, this is for the status of the order ... not necessarily WHAT EMAIL is being sent
	if ( ($status == "completed") || ($status == "processing") || ($status == "on-hold") ) {
 
		// the ID of the conference product
		$prod_arr = array( 454 );  
    
		// getting the order products
		$items = $order->get_items();
    
		// starting the bought products variable
		$bought = false;
    
		// loop through each of the items in the order
		foreach ( $items as $item ) {

			// in case we want to access stuff about produdct ids of the ordered items (not currently used)
			$product_id = $item['product_id'];
			// Here you get your data from products
			$custom_field_to_check = get_post_meta( $product_id, '_tmcartepo_data', true);

			// checking each item to see if any of the ordered products is matching the conference product id
			if ( in_array( $item['product_id'], $prod_arr ) ) {
				// if the product is found in the order, then we say it was bought
				$bought = true;
			}

		}
    
		if ( $bought ) {     
			// custom text for the email
			echo __( '<h2>Custom Title</h2>
			<p>Hey it\'s your text right here with <a href="https://example.com" target="_blank">a link</a> too!</p>', 'fswc' );
		}
	}  
}