Hello and welcome to the Community, Janet D
If the journal is posting to the Debtors (accounts receivable) account as a debit, you can match this with a credit note for the same customer using a payment.
To do this, first check that the journal has the customer selected in the Name field. Then, go to the customers page and select New transaction > Payment.
The journal entry will then show under Outstanding transactions, and the credit note under Credits. Make sure that both are ticked and then save.
For guidance on recording bad debt for customers in QuickBooks Online, see here. Thanks for reaching Intuit support. We'll be here if you need any additional assistance.