how to align a row in center in bootstrap code example

Example 1: align eliment in center of row bootstrap

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

Example 2: bootstrap center align columns

<!-- Center columns in a Row -->
<div class="row d-flex justify-content-center text-center">
    <div class="col-4">
        // Add Content
    </div>
    <div class="col-4">
        // Add Content
    </div>
    <div class="col-4">
        // Add Content
    </div>
</div>