When you place an order you will receive an order confirmation email, which will contain your order number. This information will also be available on your UNIQLO account if you have registered with us.
Please note that this email is only to acknowledge that your order has been received and is not confirmation that your order has been processed. Once your order has been shipped, we will send you a shipment confirmation email confirming your order.My UNIQLO Account
Where is my order confirmation email?