Hi Emma. You'll need to ensure the customer isn't accidentally marked as inactive, as this can hide them from your list. You should also check that your filters are set to the correct status and date range for the invoice.
To check for inactive customers in case one was accidentally marked as inactive, go to your Customers page, click the Gear icon, and select Include inactive to reveal any hidden profiles. If your missing customer appears, you can reactivate them.
Please note that if a customer is made inactive while they still have unpaid invoices, QuickBooks automatically creates adjusting entries, including a payment and a credit note, to write off the outstanding balance. These entries serve as the write-off and cannot be deleted.
To resolve this, reactivate the customer and create a new invoice for the amount paid, then mark it as paid.

Similarly, on the Invoice list page, make sure the Status filter is set to All and that you’re using a wide Date range, like This Year, in case the invoice date isn’t what you expected.

Lastly, if everything appears correct but the invoice or customer still isn’t showing, try logging in with an incognito or private browsing window or switch to another supported browser. This can help rule out browser cache issues and often refreshes your view so missing records appear.
Additionally, you can check out this helpful article for full instructions on how to record your invoice payments: Record invoice payments in QuickBooks.
If you have any other questions about your transactions, just Reply below. We're always here to help.