tryton/view/work_form.xml

<?xml version="1.0"?>
<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
this repository contains the full copyright notices and license terms. -->
<data>
    <xpath
        expr="/form/notebook/page[@id='general']/field[@name='timesheet_available']"
        position="after">
        <label name="project_invoice_method"/>
        <field name="project_invoice_method"/>
    </xpath>
    <xpath expr="/form/notebook/page[@id='general']/separator[@name='comment']"
        position="before">
        <newline/>
        <label name="invoiced_duration"/>
        <field name="invoiced_duration"/>
        <label name="invoiced_amount"/>
        <field name="invoiced_amount"/>
        <label name="duration_to_invoice"/>
        <field name="duration_to_invoice"/>
    </xpath>
    <xpath expr="/form/notebook/page[@id='general']/group/group[@id='buttons']"
        position="inside">
        <button string="Invoice" name="invoice"/>
    </xpath>
</data>