flex row to column in bootstrap 4 code example
Example 1: flex wrap bootstrap
<div class="d-flex flex-wrap">...</div>
Example 2: flex direction column bootstrap 4
<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>