odoo/ext/3rd-party-addons/global_discount/views/invoice_view.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>

    <!-- Invoice View -->
    <record id="invoice_form" model="ir.ui.view">
        <field name="name">account.invoice.form.withholding</field>
        <field name="model">account.invoice</field>
        <field name="inherit_id" ref="account.invoice_form"/>
        <field name="arch" type="xml">
            <data>
                <xpath expr="//field[@name='user_id']" position="after">
                    <label for="global_discount"/>
                    <div name='global_discount'>
                        <div>
                            <field name='global_discount' class="oe_inline" nolabel="1" attrs="{'invisible': [('state','!=', 'draft')]}"/>
                            <field name='discount_type' class="oe_inline" nolabel="1" attrs="{'invisible': ['|',('global_discount','=', False), ('state','!=', 'draft')], 'required':[('global_discount','!=', False)]}"/>
                            <field name='discount_amount' class="oe_inline" nolabel="1" attrs="{'invisible': ['|','|',('global_discount','=', False), ('state','!=', 'draft'),('discount_type','!=','fixed')]}"/>
                            <field name='discount_percentage' class="oe_inline" nolabel="1" attrs="{'invisible': ['|','|',('global_discount','=', False), ('state','!=', 'draft'),('discount_type','!=','percentage')]}"/>
                            <button name="create_discount" string="Add Line" type="object" class="oe_inline fa fa-arrow-right oe_link" attrs="{'invisible': ['|',('global_discount','=', False), ('state','!=', 'draft')]}"/>
                        </div>
                    </div>
                </xpath>
            </data>
        </field>
    </record>

    <!-- Bill View -->
    <record id="invoice_supplier_form" model="ir.ui.view">
        <field name="name">account.invoice.form.withholding</field>
        <field name="model">account.invoice</field>
        <field name="inherit_id" ref="account.invoice_supplier_form"/>
        <field name="arch" type="xml">
            <data>
                <xpath expr="//field[@name='date_due']" position="after">
                    <label for="global_discount"/>
                    <div name='global_discount'>
                        <div>
                            <field name='global_discount' class="oe_inline" nolabel="1" attrs="{'invisible': [('state','!=', 'draft')]}"/>
                            <field name='discount_type' class="oe_inline" nolabel="1" attrs="{'invisible': ['|',('global_discount','=', False), ('state','!=', 'draft')], 'required':[('global_discount','!=', False)]}"/>
                            <field name='discount_amount' class="oe_inline" nolabel="1" attrs="{'invisible': ['|','|',('global_discount','=', False), ('state','!=', 'draft'),('discount_type','!=','fixed')]}"/>
                            <field name='discount_percentage' class="oe_inline" nolabel="1" attrs="{'invisible': ['|','|',('global_discount','=', False), ('state','!=', 'draft'),('discount_type','!=','percentage')]}"/>
                            <button name="create_discount" string="Add Line" type="object" class="oe_inline fa fa-arrow-right oe_link" attrs="{'invisible': ['|',('global_discount','=', False), ('state','!=', 'draft')]}"/>
                        </div>
                    </div>
                </xpath>
            </data>
        </field>
    </record>

</odoo>