Answers for "how to center align in bootstrap"

align eliment in center of row bootstrap

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

bootstrap center

<div class="row h-100">
   <div class="col-sm-12 my-auto">
     <div class="card card-block w-25">Card</div>
   </div>
</div>

how to center vertically in bootstrap col

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

bootstrap display flex

<div class="d-flex">I'm a flexbox container!</div>