First name *
    Last name *
    E-Mail *
    Your Message *
    .form-wrapper {
      position : relative !important;
    }
    
    .form-wrapper .placeholder {
      position: absolute;
      top: 5px;
      left: 5px;
      opacity: 0.5;
      transition: opacity 1s ease;
      pointer-events: none;
    }
    
    .form-wrapper .asterisk {
      color: red !important;
    }
    
    .wpcf7-form-control-wrap.active + .placeholder { 
      opacity: 0 !important;
    }
    function class_on_active_form_fields(){
    ?>
    <script>
    window.addEventListener("DOMContentLoaded", function () { 
      (function($) {     
        $('.wpcf7-form-control').each(function() {
          $(this).on('focus', function() {
            $(this).parent().addClass('active');
          });
          $(this).on('blur', function() {
            if ($(this).val().length == 0) {
              $(this).parent().removeClass('active');
            }
          });
        });
      })(jQuery);
    });
    </script>
    <?php
    }
    add_action('wp_footer', 'class_on_active_form_fields');
    <div class="form-wrapper">[text* first-name placeholder ""]<span class="placeholder">First name <span class="asterisk">*</span></span></div>
    <div class="form-wrapper">[text* last-name placeholder ""]<span class="placeholder">Last name <span class="asterisk">*</span></span></div>
    <div class="form-wrapper">[email* your-email placeholder " "]<span class="placeholder">E-Mail <span class="asterisk">*</span></span></div>
    <div class="form-wrapper">[textarea* textarea-716 placeholder " "]<span class="placeholder">Placeholder <span class="asterisk">*</span></span></div>
    
    <div class="form-wrapper">[submit "Send"]</div>