Answers for "row items center bootstrap 4"

align items center bootstrap

<div class="d-flex align-items-start">...</div>
<div class="d-flex align-items-end">...</div>
<div class="d-flex align-items-center">...</div>
<div class="d-flex align-items-baseline">...</div>
<div class="d-flex align-items-stretch">...</div>

center div bootstrap 4

<div class="d-flex justify-content-center">...</div>