how to align content center in bootstrap code example

Example 1: bootstrap col center content

<div class="row">
    <div class="col-4 d-flex justify-content-center text-center">
        // for image and text
    </div>
</div>

Example 2: 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 3: 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>