You can pay by credit card (at the moment VISA, MASTERCARD, and AMERICAN EXPRESS) in my Art Shop. If you want to receive an invoice by email, contact me by email.
Yes, it is safe to use your credit card. In my shop, you pay with your credit card via Stripe so I do not handle, collect or restore any credit card numbers. You can learn more from Stripe here.
But remember that you have always an option to receive an invoice from me too so it is not necessary to use your credit card to purchase my artworks.