1. Download latest version at http://formidablepro.com/formidable-add-on-downloads/ Important: Versions 1.0rc4+ require Formidable v1.6+
2. In your WordPress admin, go to “Plugins” -> “Add New” and click the “Upload” link at the top of the page.
3. Click the “Browse” button and select the zip file you just downloaded.
4. Go the the “Plugins” page, find “Formidable Registration” and click “Activate”.
5. Go to “Formidable” -> “Forms” and click “edit” for the form you would like to use for user registration or editing profiles.
6. Go to “Registration Options” at the bottom of the page and set your options. 
7. Click the “Update” button at the bottom of the page.

Add a login form

frm-login Shortcode

[frm-login]

Password change form

• Set your form up with the registration add-on.
• Include an email field selected as the user email in your form. Other than that, none of the fields are required. If you don’t want this field shown, add [admin_email] as the dynamic default value and check the “admin only” box.
• To allow the user to change the password, check these boxes in the form settings: “Allow only one entry for each logged-in user” and “allow logged in users to edit previous responses.” You find find more on editing here.

Link an upload field to user avatars

add_filter( 'get_avatar', 'get_frm_avatar', 10, 5 );
function get_frm_avatar( $avatar = '', $id_or_email, $size = '96', $default = '', $alt = false ){
  $user_meta_name = 'frm_avatar'; //change frm_avatar to whatever user meta name you have given the upload field in your registration settings
  if ( is_numeric($id_or_email) ){
    $user_id = (int) $id_or_email;
  }elseif ( is_string($id_or_email) ){
    if ( $user = get_user_by_email( $id_or_email ) )
      $user_id = $user->ID;	
  }elseif ( is_object($id_or_email) && !empty($id_or_email->user_id) ){
      $user_id = (int) $id_or_email->user_id;
  }

  if ( isset($user_id) ){
    $avatar_id = get_user_meta( $user_id, $user_meta_name, true );
    $local_avatars = FrmProFieldsHelper::get_media_from_id($avatar_id, $size);
  }

  if ( !isset($local_avatars) || empty($local_avatars) ){
    if ( !empty($avatar) )  // if called by filter
      return $avatar;

    remove_filter( 'get_avatar', 'get_frm_avatar' );
    $avatar = get_avatar( $id_or_email, $size, $default );
    add_filter( 'get_avatar', 'get_frm_avatar', 10, 5 );
    return $avatar;
  }

  if ( !is_numeric($size) ) // ensure valid size
    $size = '96';

  if ( empty($alt) )
    $alt = get_the_author_meta( 'display_name', $user_id );

  $author_class = is_author( $user_id ) ? ' current-author' : '' ;
  $avatar = "<img alt='" . esc_attr($alt) . "' src='" . $local_avatars . "' class='avatar avatar-{$size}{$author_class} photo' height='{$size}' width='{$size}' />";

  return $avatar;
}

Stop the registration email

add_filter('frm_send_new_user_notification', 'frm_stop_user_notification');
function frm_stop_user_notification($send){
  return false;
}

Set the user role

add_filter('frmreg_new_role', 'frmreg_new_role', 10, 2);
function frmreg_new_role($role, $atts){
  extract($atts);
  if($form->id == 5){
    if($_POST['item_meta'][125] == 'Author') //change 125 to the ID of your field and 'Author' to the value of your radio button
      $role = 'author';
  }
  return $role;
}

User Examples