The invoicing policy

By default, Odoo configures invoicing so that the line items of the invoice will be created based on the ordered quantities from the sales order. This means that even if none of the items have shipped, the customer will still be invoiced. Alternatively, you can change the invoicing policy so that the customer is invoiced on delivered items. If you have items on a sales order that have not shipped yet, the customer will not be invoiced for those items.