Hello Leke,

Try with the following code, and don't forgot added your xml file on __manifest__.py/__openerp__.py
after restart the server please upgrade your custom module.

<record id="view_res_partner_form_inherit" model="ir.ui.view">
        <field name="name">DRS Company Custom Fields</field>
        <field name="model">res.partner</field>
        <field name="type">form</field>
        <field name="inherit_id" ref="base.view_partner_form"/>
        <field name="arch" type="xml">
            <field name="lang" position="after">
                <field name="k_code" string="Supplier"/>
            </field>
        </field>
    </record>