Screenshots
Create a Sale Order.
Go to Other Information ->Create Invoice -> Set 'Delivered quantities'
You can create invoice only after the delivery of the product. 'Create Invoice' will not be visible on sale order
At the Delivery side, create invoice will be 'To be Invoiced, which indicates the invoice can be created from the picking side.
When the delivery is done, you can create the invoice from the delivery order itself.
Create a Sale Order.
Go to Other Information ->Create Invoice -> Set 'Ordered quantities'
After confirming the sale orders, you can directly create the invoice from sale order itself.
At Delivery side, create invoice will be 'Not Applicable', which indicates invoice cannot be created from the picking side.
Invoicing policy in Customer Side