Hi there, @Procradminator. Let me share with you some information about sending customer statements in QuickBooks Online (QBO).

At this time, we're unable to send a scheduled monthly statement for each customer. You'll have to check each client with open balances or receivables. Then, send the sales form manually.
 

Here's how:

1. Sign in to QuickBooks.
2. Go to the Sales menu and select the Customers tab.
3. Select the checkboxes for the customers you want to make statements for.
4. In the Batch actions dropdown, select Create statements.
5. In the Statement Type dropdown, select the customer statement type:
   • Balance Forward: Lists invoices and payments with outstanding balances for a specific date range.
   • Open Item: Lists all open, unpaid invoices from the last 365 days.
   • Transaction Statement: Lists all transactions for the selected date range.
6. Select the dates for the statements and the date range.
7. Review the customer's email addresses.
8. Tap on Save and send.

You can also learn more about customising your form templates from here: Create and send customer statements in QuickBooks Online.

On the other hand, you can get more tips about creating recurring or scheduled invoices and other transactions from here: Create recurring transactions in QuickBooks Online.

If you have any other follow-up questions, let me know by adding a comment below. I'm more than happy to help. Have a good one!