anyiduru

What php code can I use to make the phone field REQUIRED?

I want it to output error code when phone field is left blank during registration.

Please which file and line exactly do i place the last code
“function mrb_modify_user_columns($column_headers) {
unset($column_headers[‘posts’]);
$column_headers[‘phone’] = ‘Phone’;
return $column_headers;
}
add_action(‘manage_users_columns’,’mrb_modify_user_columns’);

function mrb_user_phone_column_content($value, $column_name, $user_id) {
$user = get_userdata( $user_id );
if ( ‘phone’ == $column_name ) {
return ‘billing_phone . ‘”>’ . $user->billing_phone . ‘‘;
}
return $value;
}
add_action(‘manage_users_custom_column’, ‘mrb_user_phone_column_content’, 10, 3);”

Please I need to know!