Answers for "how to make a div in center in bootstrap"

align eliment in center of row bootstrap

<div class="row justify-content-center">
  ...inner divs and content...
</div>

centralize div bootstrap

<div class="row align-items-center justify-content-center">
    <div class="col">This will be centered vertically and horizontally</div>
</div>

how to center vertically in bootstrap col

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