To generate an invoice in the Patient Statement module:

1. Navigate to Billing > Patient Statement. 
2. Use the "To Date" filter to generate the table, and also filter based on client(s) and date range (optional).
3. Select the patient statement using the checkboxes. 
4. Select Generate Invoice using the drop-down to create a billing invoice.

Once the invoice is generated, it will be sent to the patient or their guarantor and moved to the Manage Statement module.