Welcome to the Community space, @Shirley15.

I am here to provide some insights about viewing your customer's information without creating an invoice in QuickBooks Online.

If you wish to view your customers' transaction history without creating a dummy invoice, you can access the information through your bank register or by running a Transaction List by Customer report.

Here's how:

1. Select Reports, from the left pane. 
2. Search for the Transaction list by customers report.
3. Then click Run report.

We value your opinion and suggestions about how QuickBooks Online (QBO) works. This will guide our product engineers on how to improve existing features and develop new ones to meet the needs of our customers. Here's how:

1. Sign in to your QBO account.
2. Go to the Gear icon.
3. Select Feedback under Profile.
4. Enter your suggestion. Then, click Next.

Moreover, I'm adding this helpful article as you reference in customizing your sales forms in QBO: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Please don't hesitate to return to this post if you have other concerns about viewing your customer's information in QBO. I'll be here to lend a hand.