unable to manage bootstrap 4 div elements to the responsive design - html

Question

I'm working with bootstrap 4 and following codes,
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap#4.6.0/dist/css/bootstrap.css">
<div class="card-header rounded-0 border border-dark">
<div class="row">
<div class="col-12 col-md-4 ">
<img src="{{asset('images/usa.jpg')}}" alt="..." class="rounded-circle">
</div>
<div class="col-12 col-md-8 ">
<p>This is not a game fgfhg dfghdh dhdhdf dfgdhfhg dfdfhfh dfhdfhdf dfhdfh</p>
</div>
</div>
</div>
I need display above two div elements in the same row on large screen and need separate two rows (image is above and paragraph is under the image) when it is displaying mobile device. I use following col-12 col-sm-8 col-md-6 col-lg-4 col-xl-3 item codes in side to the div but not success.
how could I manage this problem?

Answer 1

View in Full Page , You will get it
body {
padding-top: 40px;
}
.col-sm-6 {
background: #ccc;
}
.other {
background: #a4a4a4;
}
.p {
text-align: center;
padding-top: 120px;
}
.p a {
text-decoration: underline;
color: blue;
}
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" rel="stylesheet" />
<div class="container">
<div class="row">
<div class="col-sm-6">
<h1>Bootstrap Grid Demo</h1>
</div>
<div class="col-sm-6 other">
<h1>2 Columns</h1>
</div>
</div>
</div>
<p class="p">Demo by Jabir Sayed. See article.</p>