In this method, you can post an agency billing/subsidy for a child using the Ledger Records. 

Access Path : Center Dashboard > Ledger > Select a Family 

On the 'Post Ledger Item' pop-up, select the 'Agency' from the Ledger drop-down.

Fill all the necessary details in the relevant boxes and choose the 'Transation Type' and 'Child' from the respective drop-downs.

After entering the details, select the 'Post' button to post the subsidy.

Posted Agency Billing in the Ledger List