You can choose this billing method directly when writing the quote if your customer is eligible for it.
To be able to access the interface for creating a commercial proposal for a recurring mission, your client must be eligible to pay for his missions by invoice only.
Most of the time, these are large companies whose accounting processes do not allow prepayment of missions.
Moreover, it is impossible to establish such a commercial proposal with a new client through a Malt Open. We are not, indeed, able to identify his payment method at this stage.