Please modify the module so that the three fields appear in red or with a red star next to the field name to alert the user that these fields are required before saving.

(Phone, Identity Number, Nationality)

<?xml version="1.0" encoding="UTF-8"?>

<odoo>

<data>

<record id="view_partner_form_inherit_training" model="ir.ui.view">

<field name="name">res.partner.form.training.center</field>

<field name="model">res.partner</field>

<field name="inherit_id" ref="base.view_partner_form"/>

<field name="priority">99</field>

<field name="arch" type="xml">

<xpath expr="//field[@name='website']" position="before">

<field name="identity_number" placeholder="1012345678"/>

<field name="gender"/>

<field name="nationality_id"/>

</xpath>

<xpath expr="//field[@name='phone']" position="attributes">

<attribute name="placeholder">05XXXXXXXX</attribute>

</xpath>

</field>

</record>

<!-- Search View -->

<record id="view_res_partner_filter_inherit_identity" model="ir.ui.view">

<field name="name">res.partner.search.inherit.identity</field>

<field name="model">res.partner</field>

<field name="inherit_id" ref="base.view_res_partner_filter"/>

<field name="arch" type="xml">

<field name="name" position="attributes">

<attribute name="filter_domain">['|', '|',

('name', 'ilike', self),

('phone', 'ilike', self),

('identity_number', 'ilike', self)

]</attribute>

<attribute name="string">Name / Phone / ID</attribute>

</field>

<!-- Group By -->

<xpath expr="//group[@expand='0']" position="inside">

<filter string="Phone" name="group_by_phone" context="{'group_by': 'phone'}"/>

<filter string="ID Number" name="group_by_id_number" context="{'group_by': 'identity_number'}"/>

<filter string="Salesperson" name="group_by_salesperson" context="{'group_by': 'user_id'}"/>

</xpath>

</field>

</record>

</data>

</odoo>

#Python

class ResPartner(models.Model):

_inherit = 'res.partner'

identity_number = fields.Char(string="Identity Number", index=True, size=10, required=True)

gender = fields.Selection([('male', 'Male'), ('female', 'Female')], string="Gender")

nationality_id = fields.Many2one('res.country', string='Nationality', required=True)

phone = fields.Char(string="Phone", required=True)