pos/pos_customer_display/views/customer_display_view.xml

<?xml version="1.0"?>
<odoo>

    <record id="view_pos_config_form" model="ir.ui.view">
        <field name="name">pos_customer_display.pos.config.form</field>
        <field name="model">pos.config</field>
        <field name="inherit_id" ref="point_of_sale.view_pos_config_form"/>
        <field name="arch" type="xml">
            <field name="iface_cashdrawer" position="after">
                <field name="iface_customer_display"/>
                <field name="customer_display_line_length"/>
            </field>
            <group name="receipt" position="after">
                <group name="customer_display" string="Customer Display">
                    <label string="Next Customer Message" name="next_customer" colspan="2"/>
                    <field name="customer_display_msg_next_l1" string="Top Line"/>
                    <field name="customer_display_msg_next_l2" string="Bottom Line"/>
                    <label string="POS Closed Message" name="pos_closed" colspan="2"/>
                    <field name="customer_display_msg_closed_l1" string="Top Line"/>
                    <field name="customer_display_msg_closed_l2" string="Bottom Line"/>
                </group>
            </group>
        </field>
    </record>

</odoo>