Purchase of a product by a registered user

I, as a user, want to purchase a product for use.

Acceptance criteria:
The product was successfully found by the user, the product is selected and added to the cart. When you go to the cart, a button appears with the function of purchasing the selected product. The product purchase button functions and after clicking, a payment form for purchasing the product appears. Having filled out the payment form with valid values, the "order" button appears. After clicking on the "Order" button, the message "Purchase completed successfully" is displayed, the order number has been sent by email. A message with the order number has been sent to the user's registered email.