server-tools/user_threshold/views/res_company_view.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Copyright 2017 LasLabs Inc.
    License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl.html).
-->

<odoo>

    <record id="view_company_form" model="ir.ui.view">
        <field name="name">res.company.form</field>
        <field name="model">res.company</field>
        <field name="inherit_id" ref="base.view_company_form" />
        <field name="arch" type="xml">
            <xpath expr="//notebook/page[1]/group/group[1]" position="inside">
                <field string="Maximum Users" name="max_users" />
            </xpath>
        </field>
    </record>

</odoo>