Добавить произвольный класс к любому поле в Ultimate Member
add_filter('um_core_fields_hook', function($core_fields){
if ($core_fields) {
foreach ($core_fields as $key => &$field) {
if (isset($field['col2'])) {
$field['col2'][] = '_css_class';
}
}
}
return $core_fields;
}, 10, 1);
add_filter( 'um_extend_field_classes', function($classes, $key, $data){
if ($data['css_class'])
$classes .= $data['css_class'];
return $classes;
}, 10, 3 );