The system of automatic payment and receipt of goods by e-mail. view on LP. How to implement?

Question

Payment systems

Hello. You need a service to automatically pay for the goods and receive this product on the buyer's email.
Here is the site.
After the client enters and fills out the form, he should automatically go to the payment form. Pay the bill and receive the book in PDF format to your email. How to implement it? What services can be used?