How can I find/get a card number for online purchases.

[KwiKh]

Hi! So I got Paypal to make purchases online since I don't own a visa or credit card and I'm not planning to. Yesterday I wanted to pruchase something and selected to pay with Paypal. Normally it works fine but now they needed a card number from Paypal. Where do I find this card number/expire date/ etc? 

[kernowlass]

@KwiKh 

You may be requested to add a debit or credit card / bank account to verify your paypal account.