Answers for "bootstrap mb-lg"

<div class="col-lg-3 mb-4">

<div class="col-lg-3 mb-4">

bootstrap class="mb-3"

mt- = margin-top
mb- = margin-bottom
ml- = margin-left
mr- = margin-right
my- = it sets margin-left and margin-right at the same time on y axes
mX- = it sets margin-bottom and margin-top at the same time on X axes