class TaskType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('name', TextType::class, [
                'label' => 'name'
            ])
....
public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults([
       'data_class' => Task::class,
        'translation_domain' => 'task'
    ]);
}