Boostrap class center code example

Example 1: bootstrap center button

<div class="text-center"> 
	 <button type="button">centered button</button>
</div>

Example 2: 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>