Are you using the mobile app, alex113?
If you're using iPhone, follow these steps below:
- From the Menu ☰, select Invoice Payments.
- Select the customer who paid you.
- Select Edit ✎, then add payment details.
- The payment amount you enter is automatically applied to the oldest open invoice first, followed by the next oldest invoice, and so on.
- You can enter different amounts for any open invoices. Or choose the radio buttons to quickly auto-fill the balance due amounts.
- If the payment amount exceeds all of the open invoice balances, the Unapplied Amount is shown at the bottom of the page.
- When you're done, select Save.
If you're using a different device, check this article: Receive an invoice payment using the QuickBooks Online app. Doing this will automatically mark your invoices as paid.
For more mobile app functions, give this article a read: Compare mobile app features.
I'll be here if you need further assistance.