All customer related default billing details like payment terms and eInvoicing information is stored under Customer settings tab. Note that if something different is set in project settings, they will override the selections from Customer settings.
Under the Taxation header you can set an invoicing VAT if it is different from the organizations default. It is also possible to set Reverse charge option.
You can also set a specific price list created in Settings > Price lists for a customer. Note that editing the price list option will take effect only on new projects created after the change. Existing projects will not be changed by this.
In this view you can also edit Market segments for the customer (add or remove segments). You can add or edit market segments from Settings > Market segments.