What is the payment method for BitPay?

Can you please explain to me what the payment method is for BitPay? I've heard of the service before but I'm not entirely clear on how it works. Does it allow for a variety of payment options, or is it limited to just a few? I'm particularly interested in whether or not it supports credit and debit card payments, as well as any other popular payment methods that are commonly used in the cryptocurrency space. Additionally, I'd like to know if there are any fees associated with using BitPay, and if so, how they are calculated and charged.