How to add Mobile field in Registration form using Theme my login Plugin

I have created a new PHP file in the plugins folder and added the code:

function add_tml_registration_form_fields() {
tml_add_form_field( 'register', 'phone', array(
    'type'     => 'tel',
    'label'    => 'Mobile Number',
    'value'    => tml_get_request_value( 'phone', 'post' ),
    'id'       => 'phone',
    'priority' => 15,) );} add_action( 'init', 'add_tml_registration_form_fields' );

function validate_tml_registration_form_fields( $errors ) { if ( empty( $_POST['phone'] ) ) { $errors->add( 'empty_phone', '<strong>ERROR</strong>: Please enter your mobile number.' ); } add_filter( 'registration_errors', 'validate_tml_registration_form_fields' );

function save_tml_registration_form_fields( $user_id ) { if ( isset( $_POST['phone'] ) ) { update_user_meta( $user_id, 'phone', sanitize_text_field( $_POST['phone'] ) ); } } add_action( 'user_register', 'save_tml_registration_form_fields' );

But I am getting error. please refer to this image: https://www.awesomescreenshot.com/image/5706632/f5c513616090709c1ee6faa42bc6afeb

Please suggest some help.