Once you direct billed a folio, it will first move to the Uninvoiced items in Accounting. It is only once invoiced that it will go to the designated City Ledger Account and will show in the AGING report of that account.
Path: Accounting > City Ledger > AGING Report
To see all the folios that make that Uninvoiced Items amount, go to Print Invoices.
Path: Accounting > City Ledger > Print Invoices
It is important to take care of all uninvoiced items regularly to make sure all accounts are invoiced to get paid in time and to keep your AGING report up to date.