bootstrap center eleement code example
Example 1: bootstrap 4 center div
<div class="d-flex justify-content-start">...</div>
<div class="d-flex justify-content-end">...</div>
<div class="d-flex justify-content-center">...</div>
<div class="d-flex justify-content-between">...</div>
<div class="d-flex justify-content-around">...</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>