Welcome to the QuickBooks Community, Emma.
QuickBooks automatically downloads transactions approved by your bank and works in sync with your financial institution. To verify that your payment has been processed, it’s a good idea to check your Barclaycard account to confirm if it has been posted.
To manually enter the missing payment for your Barclaycard credit card, please follow these steps:
- Click the + New button.
- In the Other section, select Pay down credit card.

- Choose the Barclaycard credit card from the drop-down menu.
- Enter the payment amount and the date of the payment.
- Select the bank account used for the payment.
- Click Save and Close.

For more information, you can refer to this article: Record your payments to credit cards in QuickBooks Online.
If the payment later syncs to your Barclaycard in QuickBooks, it may appear as a duplicate. In that case, you can exclude the duplicate entry to maintain accurate records.
If you have further questions or need more assistance, you can reply to this thread, and the Community team is always here to support you.