group-field.php

<?php
// AnsPress group field.
array(
  ...
  'type'        => 'group',
  'toggleable'  => true, // Checkbox for showing and hiding group.
  'fields'       => array(
    'child-1'  => array(
      'label' => __( 'A simple child text field' ),
      'type'  => 'input',
    ),
    'child-2'  => array(
      'label' => __( 'A simple child textarea field' ),
      'type'  => 'textarea',
    ),
    'child-3'              => array(
      'label' => __( 'A simple child upload field' ),
      'type'  => 'upload',
    ),
    
    // A group field can have group field as child.
    'child-group'          => array(
      'label'              => __( 'Group of field' ),
      'type'               => 'group',
      'fields'             => array(
        'child-of-child-1' => array(
          'label'   => __( 'A simple child email field' ),
          'type'    => 'input',
          'subtype' => 'email',
        ),
        'child-of-child-2' => array(
          'label'   => __( 'A simple child password field' ),
          'type'    => 'input',
          'subtype' => 'password',
        ),
      ),
    ),
  ),
  ...
);