You can print charge reports in RangerMSP and send them to your customers (charges reports . Charge reports can be printed at the customer, service contract and trouble ticket levels. Each report displays all the relevant charges for labor, expenses and parts that were logged during the date range you've entered for the customer, contract or ticket.
Alternatively, you can use the RangerMSP-QuickBooks Link module to create QuickBooks invoices.
You can learn more about the RangerMSP-QuickBooks Link
here.