contenido de bootstrap col center
<div class="row">
<div class="col-4 d-flex justify-content-center text-center">
// for image and text
</div>
</div>
flex wrap bootstrap
<div class="d-flex flex-wrap">...</div>
alighn derecho 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>
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>
columna de dirección de flexión bootstrap
d-flex flex-column
pantalla de arranque flex
<div class="d-flex">I'm a flexbox container!</div>
pantalla flex usnig bootstrap
<div class="d-flex p-2 bd-highlight">I'm a flexbox container!</div>