oca-ocb-accounting/odoo-bringout-oca-ocb-snailmail_account/snailmail_account/wizard/account_invoice_send_views.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>
        <record model="ir.ui.view" id="account_invoice_send_inherit_account_wizard_form">
            <field name="name">account.invoice.send.form.inherited.snailmail</field>
            <field name="model">account.invoice.send</field>
            <field name="inherit_id" ref="account.account_invoice_send_wizard_form"/>
            <field name="arch" type="xml">
                <xpath expr="//div[@name='option_email']" position='before'>
                    <div name="option_letter">
                        <field name="invalid_addresses" invisible="1"/>
                        <div name="option" class="text-start d-inline-block">
                            <field name="snailmail_is_letter" />
                            <b><label for="snailmail_is_letter"/></b>
                        </div>
                        <span attrs="{'invisible': [('snailmail_is_letter','=', False)]}">
                            <span class="mr4" attrs="{'invisible': [('snailmail_cost', '=', 0)]}">
                                <b>(
                                    <span>
                                        <field name="snailmail_cost" options="{'digits':[0,0]}" class="mr4"/>
                                        <label for="snailmail_cost" class="mr4"/>
                                    </span>
                                    <i class="fa fa-info-circle" role="img" aria-label="Warning" title="Make sure you have enough Stamps on your account."/>
                                )</b>
                            </span>
                            <span class="text-end d-inline-block " attrs="{'invisible': ['|', ('composition_mode', '=', 'mass_mail'), ('partner_id', '=', False)]}" name="address">
                                <span class="text-muted" attrs="{'invisible': [('invalid_addresses', '!=', 0)]}"> to: </span>
                                <span class="text-danger" attrs="{'invisible': [('invalid_addresses', '=', 0)]}"> The customer's address is incomplete: </span>
                                <field name="partner_id" readonly="1" force_save="1" context="{'show_address': 1, 'address_inline': 1}" options="{'always_reload': True, 'no_quick_create': True}"/>
                            </span>
                            <span attrs="{'invisible': ['|', ('composition_mode', '!=', 'mass_mail'), ('invalid_addresses', '=', 0)]}">
                                <span class="text-danger">
                                    Some customer addresses are incomplete.
                                </span>
                                <button type="object" name="invalid_addresses_action" class="btn btn-link" role="button"><field name="invalid_addresses" readonly="1" options="{'digits':[0,0]}"/> Contacts</button>
                            </span>
                        </span>
                    </div>
                </xpath>
                <xpath expr="//footer/button[hasclass('send_and_print')]" position='attributes'>
                    <attribute name="attrs">{'invisible': ['|', ('is_print', '=', False), '&amp;', '&amp;', ('is_print', '=', True), ('snailmail_is_letter', '=', False), ('is_email', '=', False)]}</attribute>
                </xpath>
                <xpath expr="//footer/button[hasclass('send')]" position='attributes'>
                    <attribute name="attrs">{'invisible': ['|', ('is_print', '=', True), '&amp;', '&amp;', ('is_print', '=', False), ('snailmail_is_letter', '=', False), ('is_email', '=', False)]}</attribute>
                </xpath>
                <xpath expr="//footer/button[hasclass('print')]" position='attributes'>
                    <attribute name="attrs">{'invisible': ['|', '|', ('is_print', '=', False), ('snailmail_is_letter', '=', True), ('is_email', '=', True)]}</attribute>
                </xpath>
            </field>
        </record>

    </data>
</odoo>