account-financial-tools/account_fiscal_position_vat_check/views/account_fiscal_position.xml

<?xml version="1.0" encoding="utf-8" ?>
<!--
 Copyright 2013-2020 Akretion France (https://akretion.com/)
 @author: Alexis de Lattre <alexis.delattre@akretion.com>
 License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
-->
<odoo>
    <record id="view_account_position_form" model="ir.ui.view">
        <field name="name">customer.must.have.vat.fiscal_position_form</field>
        <field name="model">account.fiscal.position</field>
        <field name="inherit_id" ref="account.view_account_position_form" />
        <field name="arch" type="xml">
            <field name="vat_required" position="attributes">
                <!-- always display that field -->
                <attribute name="attrs">{}</attribute>
            </field>
        </field>
    </record>
    <record id="view_account_position_tree" model="ir.ui.view">
        <field name="name">customer.must.have.vat.fiscal_position_tree</field>
        <field name="model">account.fiscal.position</field>
        <field name="inherit_id" ref="account.view_account_position_tree" />
        <field name="arch" type="xml">
            <field name="name" position="after">
                <field name="vat_required" />
            </field>
        </field>
    </record>
</odoo>