For this option, the system will take into account the settings you established for each customer on the Send Invoice Via option. To confirm, go to Setup >> Customers, double click on the customer you want to verify and make sure that the desired options are checked. 

Go to Setup > Settings > Order Entry and click on the Invoice Options link.

 Enable the Scheduled Delivery of Invoices option in order to automatically send the confirmed invoices for the current day. 

 Set the time in which the system will start sending the invoices, then save your changes.

In order to make this work properly keep in mind the following scenarios:

• The system will only send invoces of the confirmed orders for the current day, it won't send future or past orders.

• If the user manually sends the order the invoice won't be sent by the automated process.

• If the orders are created or confirmed after the scheduled time, the system will not send the invoice.

• If you want the system to send the orders by fax, you must have a Faxage account. If you don't have it you can go to www.faxage.com in order to setup your account. To configure the fax service in the system go to Setup > Settings > Company Setup > Fax Service Information, enter the information requested and save. This operation will enable the fax option in the system.