Field help (MONIRT)

Enter the interval at which the invoice will be generated. The default value of the interval is 1.

The recurrence is determined thanks to this field and to the Day of the month. For instance:
Day of the month = 15,
Monthly interval = 1,
Accounting date of the reference invoice = January 1st,
The next invoice will be generated February, 15th.

This field is available when the Monthly option is selected in the Recurrence pattern section.