landing-header.html.twig

<div class="logo_wrap">
  <a class="navbar-brand" href="/">
    <img src="/sites/www.hycm.com/files/2018-01/logo_white (1).svg" alt="HYCM">
  </a>
</div>
<div class="btns d-flex">
  <a href="#shortForm" class="btn open_account_btn btn_white smooth_scroll" style="display: inline-block;">{{ 'Register'|t }}</a>
  <a href="/login" class="btn open_account_btn btn_transparent" style="display: inline-block;">{{ 'Login'|t }}</a>
</div>

LandingPageHeader.php

<?php
namespace Drupal\hycm_blocks\Plugin\Block;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Drupal\Core\Render\RendererInterface;
use Drupal\Core\Config\ConfigFactoryInterface;
/**
 * Provides a 'LandingPageHeader' block.
 *
 * @Block(
 *  id = "landing_page_header",
 *  admin_label = @Translation("Landing Page Header"),
 * )
 */
class LandingPageHeader extends BlockBase implements ContainerFactoryPluginInterface {
  /**
   * Drupal\Core\Render\RendererInterface definition.
   *
   * @var \Drupal\Core\Render\RendererInterface
   */
  protected $renderer;
  /**
   * Drupal\Core\Config\ConfigFactoryInterface definition.
   *
   * @var \Drupal\Core\Config\ConfigFactoryInterface
   */
  protected $configFactory;
  /**
   * Constructs a new LandingPageHeader object.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param string $plugin_definition
   *   The plugin implementation definition.
   */
  public function __construct(
    array $configuration,
    $plugin_id,
    $plugin_definition,
    RendererInterface $renderer,
    ConfigFactoryInterface $config_factory
  ) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->renderer = $renderer;
    $this->configFactory = $config_factory;
  }
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('renderer'),
      $container->get('config.factory')
    );
  }
  /**
   * {@inheritdoc}
   */
  public function build() {
    $build = [];
    $renderArray = [
      '#theme'  =>  'landing_header',
      '#header' =>  NULL
    ];
    $build['landing_page_header']['#markup'] = \Drupal::service('renderer')->render($renderArray);
    return $build;
  }
}