Hi,

1. Inherit the appointment.question model

Create a custom module, and inherit the model to add your custom types:

from odoo import models, fields

class AppointmentQuestion(models.Model):

    _inherit = 'appointment.question'

    answer_type = fields.Selection(

        selection_add=[

            ('html', 'HTML'),

            # You can add more custom types

        ],

        ondelete={'html': 'set default'}  # Handle deletion behavior

    )

Hope it helps