The orders are processed by shopify, which is a well established Multinational Company. All the order information including your address or phone number is stored in shopify.
Payment is processed by Stripe, another well established payment processor and the order information is also stored there.
Once the payment is processed, you will receive an email from sendowl which is connected to shopify. This email contains the purchase registration url.
The UNITESERVE platform only receives the purchase registration url which contains your email address and the product information. Using which your purchase is registered at uniteserve plaform.