flectra/addons/sale_stock/views/account_invoice_views.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <record id="invoice_form_inherit_sale_stock" model="ir.ui.view">
        <field name="name">account.invoice.form.sale.stock</field>
        <field name="model">account.invoice</field>
        <field name="inherit_id" ref="account.invoice_form"/>
        <field name="arch" type="xml">
            <data>
                <xpath expr="//page[@name='other_info']//field[@name='origin']" position="after">
                <field name="incoterms_id" widget="selection" groups="sale_stock.group_display_incoterm"/>
                </xpath>
            </data>
        </field>
    </record>

    <template id="report_invoice_document_inherit_sale_stock" inherit_id="account.report_invoice_document">
        <xpath expr="//div[@name='reference']" position="after">
            <div class="col-xs-2" t-if="o.incoterms_id" groups="sale_stock.group_display_incoterm">
                <strong>Incoterms:</strong>
                <p t-field="o.incoterms_id.code"/>
            </div>
        </xpath>
    </template>
</flectra>