pos/pos_disable_change_cashier/views/pos_config.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
    Copyright (C) 2020 - Today: GRAP (http://www.grap.coop)
    @author: Sylvain LE GAL (https://twitter.com/legalsylvain)
    License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
-->

<odoo>

    <record model="ir.ui.view" id="pos_config_view_form">
        <field name="model">pos.config</field>
        <field name="inherit_id" ref="point_of_sale.pos_config_view_form"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='iface_big_scrollbars']/../.." position="after">
                <div class="col-12 col-lg-6 o_setting_box">
                    <div class="o_setting_left_pane">
                        <field name="iface_change_cashier"/>
                    </div>
                    <div class="o_setting_right_pane">
                        <label for="iface_change_cashier"/>
                        <div class="text-muted">
                            Enable the possibility to change cashier
                        </div>
                    </div>
                </div>
            </xpath>
        </field>
    </record>


</odoo>