Tooltips rely on the 3rd party library Popper.js for positioning. You must include popper.min.js before bootstrap.js or use bootstrap.bundle.min.js / bootstrap.bundle.js which contains Popper.js in order for tooltips to work!

<button type="button" class="btn btn-primary btn-square" data-toggle="tooltip" data-placement="top" title="Tooltip on top">
    Tooltip on top
</button>
<button type="button" class="btn btn-primary btn-square" data-toggle="tooltip" data-placement="right" title="Tooltip on right">
    Tooltip on right
</button>
<button type="button" class="btn btn-primary btn-square" data-toggle="tooltip" data-placement="bottom" title="Tooltip on bottom">
    Tooltip on bottom
</button>
<button type="button" class="btn btn-primary btn-square" data-toggle="tooltip" data-placement="left" title="Tooltip on left">
    Tooltip on left
</button>