Welcome to the QuickBooks Community. I'll ensure to share steps so you're able to print your monthly invoice from the Billing & Subscription page.
You'll always have the option to view your QuickBooks Online payment history directly in your QuickBooks product so you can print it. To start with, I suggest going to the View Payment History page.
Here's how:
Click the QuickBooks Gear icon.
Choose Accounts and Settings.
Click on Billing & Subscription.
Select the View payment history link.
Filter the Event or Date Range and click Run Report.
Click the printer icon to print a copy.
Please note that the billing history will display the last six (6) months' bills. Then, the statements are visible the day after the billing date and not the same day.