<div class="container mt-5">
  <div class="row">
    <div class="col-md-9">
      <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myExtraLargeModalLabel">
        Launch demo modal
      </button>
      <!-- Modal -->

      <div class="modal fade bd-example-modal-xl" tabindex="-1" role="dialog" aria-labelledby="myExtraLargeModalLabel" aria-hidden="true" id="myExtraLargeModalLabel">
        <div class="modal-dialog modal-xl">
          <div class="modal-content">
            <div class="modal-header">
              <h5 class="modal-title">My PDF</h5>
              <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                <span aria-hidden="true">&times;</span>
              </button>
            </div>
            <div class="modal-body">
              <div class="row">
                <div class="col-md-12">

                  <iframe src="https://docs.google.com/gview?url=https://classics.berkeley.edu/sites/default/files/2020-01/sample.pdf&embedded=true" style="width: 100%;height: 560px;border: none;"></iframe>

                </div>
              </div>
            </div>
            <div class="modal-footer">
              <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
            </div>
          </div>
        </div>
      </div>

    </div>

  </div>

</div>