Resources> Org Payers> Choose Payer
Click on the Settings Tab >Click Edit >Set the Next Billing Date Back 1 day to allow for billing today.
Example if you next billing date is 5-20 and you want to bill today, you would change the next billing date to 5-19.
Next go to Processes > Invoicing
Click on the Run Invoicing Now
Once completed the invoice or invoices will generate and go to the billed status in the AR.