Can I pay by credit card after I have already been issued an invoice? Erryn Updated July 18, 2019 23:09 Follow Invoice Payment Options Yes you can. Once you receive your invoice, payment by credit card will be available. Related articles How can I check out in the OETC Shop using a credit card? Will I get charged a fee for using a credit card (or p-card) to purchase? How do I submit a purchase order (PO) to OETC? How do I purchase from the OETC Shop?