Thank you for reaching out here in the Community, @vqho425. I'm here to guide you on creating the same invoice for multiple customers in QuickBooks Online.
First, we will create an invoice template.
Here's how:
Go to the Gear icon and select Recurring Transactions.
Click New and select Invoice from the Transaction Type.
Change the template name.
Choose Unscheduled from the Type dropdown.
Add a new customer from the Customer dropdown.
Name it with Sample Customer, then select Save.
Fill in the necessary info in your invoice template, then click Save template.
Update the customer info when you're ready to send the invoice.
Feel free to reply to this post if you have other concerns besides creating the same invoice for multiple customers. I'd be glad to help you always. Have a great day!