Hi,

1. Inherit the event question and add the custom_date field.

class EventQuestion(models.Model):
    _inherit = 'event.question'

  custom_date = fields.Date(string='Date')

2. Add the following to the views directory,

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <record id="event_question_view_form" model="ir.ui.view">
<field name="name">event.question.view.form,inherited</field>
<field name="model">event.question</field>
<field name="inherit_id" ref="website_event.event_question_view_form"/>
        <field name="arch" type="xml">
            <field name="is_mandatory_answer" position="before">
                <field name="custom_date"/>
            </field>
        </field>
    </record>
</odoo>

Hope it helps