Triggering popup modal dialogs on button clicks in Bootstrap 5 can be accomplished declaratively using HTML data-bs-* attributes or programmatically via the JavaScript Modal instance API.

HTML & Bootstrap 5 Modal Markup

modal_example.htmlhtml
<!-- Trigger Button -->
<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#confirmModal">
    Open Confirmation Modal
</button>
 
<!-- Modal Structure -->
<div class="modal fade" id="confirmModal" tabindex="-1" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title">Confirm Action</h5>
                <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
            </div>
            <div class="modal-body">
                Are you sure you want to proceed?
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Cancel</button>
                <button type="button" class="btn btn-danger">Confirm</button>
            </div>
        </div>
    </div>
</div>