The email address you use with paypal identifies your paypal account and is all someone needs to pay you. Or you can send a money request from your paypal account to their paypal email address for them to pay.
Advice is voluntary. Kudos / Solution appreciated.
Easiest - create and send the buyer an invoice. You can do that within your PayPal Account.
Assuming you have a US Personal Account - Login to your account. Click on "Send and Request". Click on "More". Look for "Create an Invoice" Click on "Get Started" Click on "+ Create" or "Create Invoice". Complete the form. You "Preview" the form and when you're ready "Send".
