Can you please provide us what are the instructions or steps you've already performed? I'd appreciate any further details so I can share an accurate solution.
Once you uploaded your transactions in QuickBooks, the system automatically shows a match to any record you’ve already entered in QuickBooks. Including, matching the deposit/payments to an open invoice of the customer. That being said, you can click the match button so this invoice payment will link to the customer's invoice.
Here's how:
Click the Banking menu at the left panel. Then, the Banking section.
Go to the For Review tab. Then, choose the entry that shows Match and review the Records found.
Select the link next to each record to get more details.
Review the Deposit to field on the forms. Your transaction in QuickBooks is already in the account listed.
When you’re done, click Match.
Once the system doesn't show a match to an invoice payments, I suggest using the Find Match option to display all the possible matched transactions. To do that, follow the steps below:
Go to Banking and select the Banking tab.
Click Find other records button.
In the Match Transactions window, put a checkmark on the transactions that should match the downloaded transaction.
If the transaction you want to match is outside the date range displayed, update it. Select the date field to manually change the From and To dates.
Select Save if the total amount of both transactions is the same.