from odoo import api, fields, models class ContractContract(models.Model): _inherit = "contract.contract" payment_mode_id = fields.Many2one( comodel_name="account.payment.mode", string="Payment Mode", domain=[("payment_type", "=", "inbound")], index=True, ) @api.onchange("partner_id") def on_change_partner_id(self): self.payment_mode_id = self.partner_id.customer_payment_mode_id.id def _prepare_invoice(self, date_invoice, journal=None): invoice_vals, move_form = super()._prepare_invoice( date_invoice=date_invoice, journal=journal ) if self.payment_mode_id: invoice_vals["payment_mode_id"] = self.payment_mode_id.id return invoice_vals, move_form