You've just resent an open invoice that's why its status remains as sent in QuickBooks Online (QBO), @Leah. Let me share further details about this.

An invoice status will update (from Sent to Viewed to Paid to Deposited) once there's an activity performed for that specific transaction. The system automatically recognized an activity once your customer viewed the invoice. Then, when you've recorded a payment transaction and deposit it to the appropriate account. Let's visit the Invoices page to identify the status of each of your invoices in QBO. Here's how:

1. Go to the Sales menu.
2. Select the Invoices tab.
3. Find invoice, then select it to view its activity. Please see the screenshot below for your reference.

After that, I'd recommend pulling up the Invoices and Received Payments report. This way, you can effectively manage your invoices and the payments that go with them. Just go to the Who owes you section from the Reports menu's Standard tab.

Also, you're able to create attractive and professional-looking invoices in QBO. This way, you can add info that matters most to your business. If you wish to learn more about this, I'd recommend checking out this article: Customise invoices in QuickBooks Online.

I'm just around to help if you have other concerns about managing your invoices and other sales transactions in QBO.