You will have to realize a payment form including both credit card payment using Stripe and Paypal payment. It will have to include a telephone number field (double check, customers will have to fill this field twice with the same telephone number in order to move forward with the payment). Customer must receive receipt of the payment, including transaction ID via e-mail, and i have to receive notification of the payment with associated transaction ID. The form will have to collect billing informations (Name, Surname, Address, ZIP code, e-mail address). Customers will have to choose the product and related price from a dropdown menu included inside the form.
You will have to also implement a coupon code where people will receive a special prize ONLY for the first time they use a telephone number.
I actually use WP Bakery editor, you will have to realize the form totally in raw HTML.