Dears, 
I inherited survey.user_input , this field get value from survey web form, For exmaple
1. Text field views before Start survey button 

2. Submit survey, views survey.user_input form

class recruitment_survey(models.Model):

    _inherit = 'survey.user_input'

    register = fields.Char('Register')

xml code:

<record id="recruitment_survey_inherit_view_form" model="ir.ui.view">

<field name="name">survey_user_input_form</field>

<field name="model">survey.user_input</field>

<field name="inherit_id" ref="survey.survey_user_input_form" />

<field name="arch" type="xml">

<xpath expr="//form/sheet/group/group/field[@name='token']" position="after">

<field name="register"/>

</xpath>

</field>
 </record>