how to vertical center in bootstrap4 code example

Example 1: how to center vertically in bootstrap col

<div class="my-auto">
  ...inner divs and content...
</div>

Example 2: bootstrap 5 vertical align

<span class="align-baseline">baseline</span><span class="align-top">top</span><span class="align-middle">middle</span><span class="align-bottom">bottom</span><span class="align-text-top">text-top</span><span class="align-text-bottom">text-bottom</span>