You're on the right track, Clio. I'm happy to clarify the steps to get you started.

Different regions use varying terminology. When my colleague mentioned clicking on + New, she was referring to the Vendor credit option under the Vendors category, this is the term used for users in the United States (US).

For users outside the U.S., the equivalent term is Supplier credit. Therefore, after you click the + New button, select Supplier Credit under the Suppliers category.

Review this link for in-depth information on recording a refund or credit: Enter supplier credits and refunds in QuickBooks Online.

You can also use these resources to track all money paid to a supplier for the year and manage outstanding supplier balances:

• Run a report with supplier totals in QuickBooks Online.
• Manage outstanding balances for customers and suppliers in QuickBooks Online.

If you have further questions about working with supplier and customer credits, please don't hesitate to ask here in the Community. I will respond to you promptly.