Answers for "what is d-flex in bootstrap 4"

justify-content-between 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>

bootstrap display flex

<div class="d-flex">I'm a flexbox container!</div>