Periodic Invoices
When you send a customer an invoice every month (or for another period), you can pre-set a periodic invoice using the free 'subscriptions' module. Your customer will then automatically receive a monthly invoice (or for another pre-set period, until the end date you have entered). This means that you will no longer have to create and send that invoice every week, month, year, ... Sending these invoices is also automated by the program, so you'll only have to receive and monitor the payments.