social_conversational_form.module

<?php

/**
 * @file
 * Module file for Social Conversational Form.
 */

use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_form_FORM_ID_alter().
 *
 * {@inheritdoc}
 */
function social_conversational_form_form_user_register_form_alter(array &$form, FormStateInterface $form_state, $form_id) {
  // Set the context for the conversational form.
  $form['#prefix'] = '<div cf-context>';
  $form['#suffix'] = '</div>';

  if ($_GET['conv'] == 'off') {

  }
  else {
    // Attach the library.
    $form['#attached']['library'][] = 'social_conversational_form/social_conversational_form';
  }
  $form['account']['mail']['#attributes']['cf-questions'] = 'Hi there {firstname}!&&What is your email address?';
  $form['account']['name']['#attributes']['cf-questions'] = 'What do you want your username to be?';

  $form['firstname'] = array(
    '#type' => 'textfield',
    '#title' => t('First name'),
    '#required' => FALSE,
    '#weight' => -100,
    '#attributes' => [
      'id' => 'firstname',
      'cf-questions' => "Hi there!&&Nice to see you want to register at our community.&&What is your first name?"],
      'cf-error' => 'Make sure your first name does not contain numbers',
  );

  $form['profession'] = [
    '#type' => 'select',
    '#title' => t("What is your profession?"),
    '#options' => [
      '1' => t('Icecream truck driver'),
      '2' => t('Badminton supporter'),
      '3' => t('Stay at home mom'),
      '4' => t('Stay at home dad'),
    ],
  ];
}