Welcome to the Community, Amy! I'd gladly help you in looking for a specific invoice in QuickBooks Online.
In QuickBooks Online, you can head to the magnifying glass icon at the upper-right corner of your screen to search for transactions. When you click it, your recent transactions will also appear if you ever need to look back on a previous one.
To search for a specific invoice, you can follow these steps:
Navigate to the magnifying glass icon at the top-right corner of your screen.