I cannot add a new credit card or new bank account under the Pay Down credit card function

Hello jip,

Welcome to Community.  The Pay down credit card feature in QuickBooks Online, is a great way to record payments against your credit cards, and ensure your books are correctly balanced.  I would be glad to help!

The Pay down credit card feature is designed to work with home currency credit cards.  When your home currency is registered as CAD, you won't be able to choose any USD cards or other information while using this feature.  However, you can record your payments, by creating a cheque, or using the transfer option. To see how, click here.  

Should you require additional assistance, please don't hesitate to contact our Customer Care team at 1-855-253-1536 from Monday to Friday between the hours of 9 AM and 8 PM EST.  They would enjoy the opportunity to work with you personally, so you can complete your QuickBooks goals as soon as possible!

Feel free to touch base with us again, if you have other questions or concerns. We would be happy to assist!