I tried but not working am using on the xml?? 

from odoo import fields, models, api, _from odoo.exceptions import UserError
class SchoolProfile(models.Model):    _name = "school.profile"
    name = fields.Many2one("school.profile", string="School Name", required=True)

Hi,

The following ways allow you to make a field required: either updating in Python or XML.

<field name="employee_id" required="1"/>

OR

employee_id = fields.Many2one('hr.employee', string='Employee', required=1)

https://www.youtube.com/watch?v=TR1TVykJmgE