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>
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>
bootstrap justify-content-center para md
<div class="row justify-content-md-center"></div>
alinear flex end bootstrap
<div class="d-flex justify-content-end">...</div>
justificar el espacio de contenido entre la clase bootstrap
<div class="row d-flex justify-content-between"></div>
bootstrap justify-centro de contenido para lg
<div class="row justify-content-lg-center"><div>