It's great to have you here in the Community, Cheryl. I can share information on how to handle overpayment in QuickBooks Online (QBO).
To allocate the overpayment properly, we need to set up a supplier profile first for your creditor, then let's create a supplier credit for the overpayment. To record this credit, you may follow the steps provided in this article: Enter supplier credits and refunds in QBO.
Then, we'll use the Pay Bills option to link an existing supplier bill to the credit you've created in the next bill transaction.
Moreover, this article can be helpful if you want to edit supplier transactions in the future: Manage supplier's transactions.
Please know that we're always here to help if you require further assistance managing the supplier's credit or other QuickBooks-related questions. Keep safe.