how to style bootstrap tooltip code example

Example 1: bootstrap button tooltip

<!-- Bootstrap button Tooltip 
You can look here for in depth info: 
https://getbootstrap.com/docs/4.0/components/tooltips/

OR use the bellow example : -->
<button type="button" class="btn btn-secondary" data-toggle="tooltip" data-placement="top" title="Tooltip on top">
  Tooltip on top
</button>

Example 2: bootstrap 4 tooltip

<button type="button" class="btn btn-secondary" data-toggle="tooltip" data-placement="top" title="Tooltip on top">
  Tooltip on top
</button>
<button type="button" class="btn btn-secondary" data-toggle="tooltip" data-placement="right" title="Tooltip on right">
  Tooltip on right
</button>
<button type="button" class="btn btn-secondary" data-toggle="tooltip" data-placement="bottom" title="Tooltip on bottom">
  Tooltip on bottom
</button>
<button type="button" class="btn btn-secondary" data-toggle="tooltip" data-placement="left" title="Tooltip on left">
  Tooltip on left
</button>
<button type="button" class="btn btn-secondary" data-toggle="tooltip" data-html="true" title="<em>Tooltip</em> <u>with</u> <b>HTML</b>">
  Tooltip with HTML
</button>

Example 3: bootstrap 4 tooltip

// JQuery
$(function () {
  $('[data-toggle="tooltip"]').tooltip()
})

Example 4: bootstrap tooltip

$(function () {
  $('[data-toggle="tooltip"]').tooltip()
})