odoo-contact-addons/partner_contact_birthplace/views/res_partner.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl.html). -->
<odoo>

  <record id="personal_information_form_inherit" model="ir.ui.view">
    <field name="name">res.partner.form.inherit Birth place</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="partner_contact_personal_information_page.personal_information" />
    <field name="priority">18</field>
    <field name="arch" type="xml">
      <group name="personal_information_group" position="replace">
        <group name="personal_information_group">
          <group name="personal_information_col1">
            <field name="birthdate_date" />
          </group>
          <group name="personal_information_col2">
            <field name="age" />
          </group>
        </group>
      </group>
      <field name="birthdate_date" position="after">
        <field name="birthplace" />
      </field>
    </field>
  </record>

</odoo>