odoo18/addons/l10n_es/models/res_config_settings.py

from odoo import fields, models


class ResConfigSettings(models.TransientModel):
    _inherit = 'res.config.settings'

    l10n_es_simplified_invoice_limit = fields.Float(
        related='company_id.l10n_es_simplified_invoice_limit',
        readonly=False,
    )