You can add a 3rd Party (Agency) Billing using the 'Add Program' and 'Add New Recurring Billing' options available on the program and billing page.
Access Path : Center Dashboard > Children > Program & Billing
Add Program :
On the 'Add Child Program' page, select the Age Group, Program, and Program End Date.
After adding the program to the child, you need to enter the 'Fees' details and select the 'Subsidy' status of the Selected Program for the child.
Added Agency Billing,
On the Add Child Recurring Billing pop-up, select the 'Billing Type'.
On the next page, Enter all relevant details and select the 'Ledger Type' as 'Agency'.
Successfully Posted 3rd Party Recurring Billing :