Hi,

You can achieve this by extending the base model, since every Odoo model ultimately inherits from it.

This way, your new field will automatically be added to all models in the system.

Example:

addons/external_id_field/models/base.py

from odoo import models, fields

class BaseModel(models.AbstractModel):

    _inherit = 'base'

    external_id = fields.Char("External ID", copy=False, index=True)

Explanation:

• _inherit = 'base': The base model is the root for all Odoo models. Adding a field here makes it available across all models (e.g., res.partner, sale.order, account.move, etc.).
• copy=False: Prevents duplication of the field’s value when a record is duplicated.
• index=True: Creates a database index for faster lookups.

This is the cleanest and recommended approach, since it doesn’t require manually modifying every individual model.

Hope it helps

Hi Reinaldo Menendez

You need add external_id field in all models 

so you need to override _inherit = "ir.model" models then add 

example:

class IrModel(models.Model):

    _inherit = 'ir.model'

     'external_id' = fields.Char() 

Thanks.