Modal

<div class="modal" tabindex="-1" role="dialog">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">×</span>
        </button>
      </div>
      <div class="modal-body">
        <p>Modal body text goes here.</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>
Live Demo
<button type="button" class="btn btn-primary mr-2 mb-2" data-toggle="modal" data-target="#exampleModal">
  Launch demo modal
</button>

<div class="modal" tabindex="-1" role="dialog" id="exampleModal">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">×</span>
        </button>
      </div>
      <div class="modal-body">
        <p>Modal body text goes here.</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>
Scrolling long content
<div class="modal" tabindex="-1" role="dialog">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">×</span>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>
Vertically centered
<div class="modal fade" id="exampleModalCenter" tabindex="-1" role="dialog" aria-hidden="true">
  <div class="modal-dialog modal-dialog-centered" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalCenterTitle">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <i class="ti-close"></i>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close
        </button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>
Optional sizes
<!-- .modal-xl -->
<div class="modal fade" tabindex="-1" role="dialog" aria-hidden="true">
  <div class="modal-dialog modal-xl">
    <div class="modal-content">
      <div class="modal-header">
        <h6 class="modal-title">Extra large modal</h6>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <i class="ti-close"></i>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close
        </button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

<!-- .modal-lg -->
<div class="modal fade" tabindex="-1" role="dialog" aria-hidden="true">
  <div class="modal-dialog modal-lg">
    <div class="modal-content">
      <div class="modal-header">
        <h6 class="modal-title">Large modal</h6>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <i class="ti-close"></i>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close
        </button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

<!-- .modal-sm -->
<div class="modal fade" tabindex="-1" role="dialog" aria-hidden="true">
  <div class="modal-dialog modal-sm">
    <div class="modal-content">
      <div class="modal-header">
        <h6 class="modal-title">Small modal</h6>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <i class="ti-close"></i>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close
        </button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>
Varying modal content
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@mdo">
  Open modal for @mdo
</button>

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@fat">
  Open modal for @fat
</button>

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@getbootstrap">Open modal for
  @getbootstrap
</button>

<!-- modal -->
<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">New message</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <i class="ti-close"></i>
        </button>
      </div>
      <div class="modal-body">
        <form>
          <div class="form-group">
            <label for="recipient-name" class="col-form-label">Recipient:</label>
            <input type="text" class="form-control" id="recipient-name">
          </div>
          <div class="form-group">
              <label for="message-text" class="col-form-label">Message:</label>
              <textarea class="form-control" id="message-text"></textarea>
            </div>
         </form>
       </div>
       <div class="modal-footer">
          <button type="button" class="btn btn-secondary" data-dismiss="modal">Close
          </button>
          <button type="button" class="btn btn-primary">Send message</button>
       </div>
     </div>
  </div>
</div>