flectra/addons/website_payment/views/website_payment_view.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <data>
        <record id="website_settings_payment" model="ir.ui.view">
            <field name="name">website.form</field>
            <field name="model">website</field>
            <field name="inherit_id" ref="website.view_website_form"/>
            <field name="arch" type="xml">
                <xpath expr="//div[@name='other']" position='before'>
                    <div name="shop">
                        <separator string="E-Commerce"/>
                        <group name="shop">
                            <button type="action"
                                    name="%(payment.action_payment_acquirer)d"
                                    string="Configure payment acquirers" class="oe_link"/>
                        </group>
                    </div>
                </xpath>
            </field>
        </record>

        <record id="website_acquirer_form" model="ir.ui.view">
            <field name="name">payment.acquirer.form</field>
            <field name="model">payment.acquirer</field>
            <field name="inherit_id" ref="payment.acquirer_form"/>
            <field name="arch" type="xml">
                <xpath expr="//field[@name='provider']" position='after'>
                    <field name="website_id" widget="many2many_tags"/>
                </xpath>
                <xpath expr="//group[@name='acquirer_left']" position="after">
                    <group nama="acquirer_right">
                        <div class="panel panel-danger">
                            <div class="panel-heading">
                                <span>
                                    Website is required in order to use payment gateway in e-commerce store.
                                </span>
                            </div>
                        </div>
                    </group>
                </xpath>
            </field>
        </record>

    </data>
</flectra>