mail_template_data.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data noupdate="1">
        <record id="account.email_template_edi_invoice" model="mail.template">
            <field name="body_html"><![CDATA[
<p>Dear ${object.partner_id.name}
% set access_action = object.with_context(force_website=True).get_access_action()
% set is_online = access_action and access_action['type'] == 'ir.actions.act_url'
% set access_url = is_online and object.get_mail_url() or '/report/pdf/account.report_invoice/' + str(object.id)

% if object.partner_id.parent_id:
    (<i>${object.partner_id.parent_id.name}</i>)
% endif
,</p>
<p>Here is your 
% if object.number:
invoice <strong>${object.number}</strong>
% else:
pro-forma invoice
% endif
% if object.origin:
(with reference: ${object.origin} )
% endif
amounting in <strong>${format_amount(object.amount_total, object.currency_id)}</strong>
from ${object.company_id.name}.
</p>

% if is_online:
    <br/><br/>
    <center>
      <a href="${access_url}" style="background-color: #1abc9c; padding: 20px; text-decoration: none; color: #fff; border-radius: 5px; font-size: 16px;" class="o_default_snippet_text">View Invoice</a>
    </center>
% endif
    <br/><br/>

% if object.invoice_reference_type=='structured' and object.reference:
    <p>Please use the following communication for your payment : <b>${object.reference}</b></p>
% endif

<p>Please remit payment at your earliest convenience.</p>
<p>Thank you,</p>
% if object.user_id and object.user_id.signature:
    ${object.user_id.signature | safe}
% endif
]]></field>
        </record>
    </data>
</odoo>