Hi,

If you want to use three-letter codes (e.g. USA, IND, FRA), you can extend the model in a custom module and simply update the size constraint to 3:

from odoo import models, fields

class ResCountry(models.Model):

    _inherit = "res.country"

    code = fields.Char(

        string='Country Code',

        size=3,

        required=True,

        help='The ISO country code in three chars. \nYou can use this field for quick search.'

    )

You can change size=2 to size=3 by inheriting res.country in a custom module. But keep in mind that Odoo and external services assume the 2-letter ISO format, so it’s recommended to add a separate code_alpha3 field for 3-letter codes instead of overriding the default one.

Hope it helps