If you want to setup a rule to automatically generate invoices for selected reservations.
1. Go to 'Administration>Drop Down Lists' select 'Automated Invoicing Rule'.
2. Click 'New Rule' and fill in:
Name
Start: Which days that should be included in the invoice.
First included day; relative date from current day.
+0d means today's date
-1m+1d means the first of last month
End: Which days that should be included in the invoice.
Last included day; relative date from current day.
+1m -1d means the last of this month
+0d means today's date
Date: The invoice date
+0d means today's date
Due date: The due date of the invoice
+14d means 14 days from today's date
Run day: Which day of the month the invoices should be generated
0 is last day of month
1 is first day of month
-1 is one day before last day of month
Amount threshold: If invoice amount is less then this value invoice will not be generated
3. In the reservations you will see field 'Automated invoicing'. If you select a rule here invoices for this reservation will be generated accordingly.