You will be making a payment thru the PayPal system.  You don't need a PayPal account.

You may make a payment using your credit card (VISA or MASTERCARD), or your PayPal account.

After clicking on the button below, the first screen to appear will ask for a brief description and the amount you want to pay.  The description can be your invoice number or some other general description.  After entering the description and amount, click on the link at the bottom of that page that says, "use your credit card or bank account (where available)."  If you wish to use your PayPal account, enter your email address and PayPal password instead of clicking on the aforementioned link.

Click the button below to begin.