Step 1:
From the invoice sent via email, click the “view and pay invoice” button.
Step 2:
In the top left corner, hit the “Pay $” button.
Step 3:
*Important Part. Do not click “log in”. Instead, click the button below: “pay with credit or debit card”.
Step 4:
You will now be on the “Guest Checkout” page where you can pay with a credit or debit card without having a PayPal account.