Modal

Add dialogs to your site for lightboxes, user notifications, or custom content.

<button type="button" class="btn btn-primary rounded-pill mb-4" data-bs-toggle="modal" data-bs-target="#exampleModal">
  Demo modal
</button>

<div class="modal fade" id="exampleModal" tabindex="-1">
  <div class="modal-dialog modal-dialog-centered">
    <div class="modal-content">
      <div class="modal-header border-0">
        <h3 class="modal-title">>Sign In</h3>
        <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer border-0 justify-content-between">
        <a href="#" class="link-secondary small">Don't have an account?</a>
        <a href="#" class="link-secondary small">Forgot password?</a>
      </div>
    </div>
  </div>
</div>

Bootstrap Documentation