Who tied paypal to the store?

Question

PayPal

I have a friend who makes pictures for t-shirts, sort of original. I wanted to make him a site with payment via paypal. What do I need for this? Does a friend need to register an IP to accept payments, and how does this happen in general? I read somewhere that everything is very simple, but I did not see specific examples. Also interested in receiving delivery data from the user, after paying for the goods.
Thank you!