How to add gap between cards - html

Question

I need space between the cards as shown in the picture, how do I add spacing so that structure remains the same
<div class="container" style="padding: 16px;">
<div class="row">
<div class="center">
<div class="card text-white bg-primary mb-r" style="width:100px;height:100px;margin: auto;">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h7 class="card-text" style="align-content:flex-end">916</h7>
</div>
</div>
</div>
<div class="center">
<div class="card text-white bg-primary mb-r" style="width:100px;height:100px;margin: auto;">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h7 class="card-text" style="align-content:flex-end">916</h7>
</div>
</div>
</div>
<div class="center">
<div class="card text-white bg-primary" style="width:100px;height:100px;margin: auto;">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h7 class="card-text" style="align-content:flex-end">916</h7>
</div>
</div>
</div>
<div class="center">
<div class="card text-white bg-primary" style="width:100px;height:100px;margin: auto;">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h7 class="card-text" style="align-content:flex-end">916</h7>
</div>
</div>
</div>
</div>
</div>
The picture below is the code I have written, I need spacing between them.

Answer 1

To have spacing between cards just use standard Bootstrap layout, that is using row and columns. Columns have gutters by default. Read more: https://getbootstrap.com/docs/4.3/layout/overview/
There were many errors like <h7> tags, using incorrect css properties etc. Just go through my code and see the changes I made.
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<div class="container">
<div class="row">
<div class="col-3">
<div class="card w-100 text-white bg-primary">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
</div>
<div class="col-3">
<div class="card w-100 text-white bg-primary">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
</div>
<div class="col-3">
<div class="card w-100 text-white bg-primary">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
</div>
<div class="col-3">
<div class="card w-100 text-white bg-primary">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
</div>
</div>
</div>

Answer 2

I know you asked that the structure didn't change however I believe some edits needed to be made, here is a jsFiddle with some suggestions: https://jsfiddle.net/kcozqd9L/2/
CSS
.container{
padding: 16px;
}
.card{
position: relative;
display: inline-block;
width:100px;
height:100px;
margin: auto;
}
/*.card-body{
}
.card-title{
}*/
.card-text{
align-content:flex-end
}
HTML
<!--
Bootstrap docs: https://getbootstrap.com/docs
-->
<div class="container">
<div class="row">
<div class="center">
<div class="card text-white bg-primary mb-r">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
<div class="card text-white bg-primary mb-r">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
<div class="card text-white bg-primary">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
<div class="card text-white bg-primary">
<div class="card-body">
<h4 class="card-title">DEL</h4>
<h6 class="card-text">916</h6>
</div>
</div>
</div>
</div>
</div>