Wordpress Add new User hooks

Use this hook

add_action('user_new_form', 'xxxx');

Ok, here is the full code to add a permission checkbox for user mailChimp registration on user add/edit

    //Add a mailchimp permission field, on user creation, user profile update    add_action('user_new_form', 'mailchimp_permission_field');    add_action('show_user_profile', 'mailchimp_permission_field');    add_action('edit_user_profile', 'mailchimp_permission_field');    function mailchimp_permission_field($user) {        ?>        <table class="form-table">            <tr class="form-field">                <th scope="row"><label for="mail_chimp">Mail Chimp </label></th>                <td>                    <label for="mail_chimp">                        <input style="width: auto;" type="checkbox" name="mail_chimp" id="mail_chimp"                             <?php if(current_filter() == 'user_new_form' || get_the_author_meta('mail_chimp', $user->ID )): ?>                            checked = "checked"                            <?php endif; ?> />                        Subscribe to MailChimp.                    </label>                </td>            </tr>        </table>    <?php }// handle mailchimp registrations on user creation    add_action( 'user_register', 'subscribe_to_mailchimp_after_registration', 10, 1 );    function subscribe_to_mailchimp_after_registration( $user_id ) {        if (isset($_POST['email']) && isset($_POST['mail_chimp']) && $_POST['mail_chimp'] == 'on') {            mailchimp_subscribe($_POST['email']);        }    }//Save new field for user in users_meta table    add_action('user_register', 'save_mailchimp_permission_field');    add_action('edit_user_profile_update', 'save_mailchimp_permission_field');    function save_mailchimp_permission_field($user_id) {        if (!current_user_can('edit_user', $user_id)) {            return false;        }        if (isset($_POST['mail_chimp']) && $_POST['mail_chimp'] == 'on') {            update_usermeta($user_id, 'mail_chimp', true);            mailchimp_subscribe(get_userdata($user_id)->user_email);        }        else {            update_usermeta($user_id, 'mail_chimp', false);            mailchimp_unsubscribe(get_userdata($user_id)->user_email);        }    }

As far as I can see there are no action hooks that will trigger on the new user page. Searched in user-new.php for do_action.

According to the documentation, you can hook to the user_new_form action, of course your WordPress version should be above version 3.7.0.

This hook fires at the end of the new user form. It passes a contextual string to make both types of new user forms uniquely target-able. Contexts are add-existing-user (Multi-site) and add-new-user (single site and network admin).

  add_action('user_new_form', 'your_function_name');