Unfortunately, once you have successfully paid for an order, you cannot add more products to it. If you wish to add another product to an order that has already been paid, you will need to cancel the existing order and make a new one instead.
To do this, please contact the seller directly via Shopee Chat and inform them that you wish to cancel the current order so that you can place a new one with additional products.
⚠️Do not transact outside of Shopee App and ensure all payments are made within Shopee App. If you are asked to make a transaction outside of Shopee App, please do not hesitate to report the seller to Shopee.