how to center content in a div bootstrap 4 code example

Example 1: centralize div bootstrap

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

Example 2: alighn right boostrap 4

<div class="float-left">Float left on all viewport sizes</div><br>
<div class="float-right">Float right on all viewport sizes</div><br>
<div class="float-none">Don't float on all viewport sizes</div>