/** BASE FIELD */  

  $entity_type_id = 'applicant';
  $field_name = 'main_company_address';
  $schema = \Drupal::database()->schema();
  $schema_repository = \Drupal::service('entity.last_installed_schema.repository');
  $key_value = \Drupal::keyValue('entity.storage_schema.sql');
  $key_name = $entity_type_id . '.field_schema_data.' . $field_name;
  $storage_schema = $key_value->get($key_name);
  $storage_schema['applicant']['fields']['main_company_address__cadastral_municipality'] = [
    'type' => 'varchar',
    'length' => 255,
    'not null' => FALSE,
  ];
  $key_value->set($key_name, $storage_schema);
  $schema->addField($entity_type_id, 'main_company_address__cadastral_municipality', $storage_schema['applicant']['fields']['main_company_address__cadastral_municipality']);
  $entity_field_manager = \Drupal::service('entity_field.manager');
  $field_definitions = $entity_field_manager->getBaseFieldDefinitions($entity_type_id);
  $storage = $field_definitions[$field_name]->getFieldStorageDefinition();
  $schema_repository->setLastInstalledFieldStorageDefinition($storage);


/** CONFIG FIELD */


  $entity_type_id = 'basic';
  $field_name = 'cf_settlement';
  $schema = \Drupal::database()->schema();
  $key_value = \Drupal::keyValue('entity.storage_schema.sql');
  $key_name = $entity_type_id . '.field_schema_data.' . $field_name;
  $storage_schema = $key_value->get($key_name);
  $storage_schema['basic__cf_settlement']['fields']['cf_settlement_cadastral_municipality'] = [
    'type' => 'varchar',
    'length' => 255,
    'not null' => FALSE,
  ];
  $key_value->set($key_name, $storage_schema);
  $schema->addField('basic__cf_settlement', 'cf_settlement_cadastral_municipality', $storage_schema['basic__cf_settlement']['fields']['cf_settlement_cadastral_municipality']);