tryton/modules/account_payment_clearing/view/statement_line_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/field[@name='invoice']" position="after">
        <newline/>
        <label name="payment"/>
        <field name="payment"/>
        <label name="payment_group"/>
        <field name="payment_group"/>
    </xpath>
</data>