Make HTML Input Elements the same size - html

Question

I have 2 HTML containers, but because I have span elements followed by a text input (I think this is the issue?), I'm unable to get the content in the containers centered how I want. Is there a way to push the margin or padding in on these elements? Or is there a simpler way. In the JSFiddle, they spans are pretty large, but I'd like them to be around the size of the picture below. I'm using bootstrap.
<div class="container" >
<div class="row">
<div class="col-sm">
<h2>TITLE</h2>
</div>
</div>
<div class="row">
<div class="col-sm">
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text">text</span>
</div>
<input type="text" class="form-control" id='text' readonly>
</div>
</div>
</div>
JSFIDDLE: https://jsfiddle.net/oy4u1sm9/4/
Idealformatting (without the large span element, of course)

Answer 1

Using <span> tags as labels is not best practice as they are inline elements. Try to always use <label> tags. Here is your code tweaked to match your desired styling. More comments in the fiddle below.
<div class="row mb-5">
<div class="col-sm-6" align="center">
<label class="h3">TITLE</label>
<div class="input-group">
<input type="text" class="form-control" id="text" placeholder="text" required>
</div>
</div>
<div class="col-sm-6" align="center">
<label class="h3">TITLE</label>
<div class="input-group">
<input type="text" class="form-control" id="text" placeholder="text">
</div>
</div>
</div>
I made some comments in the code for clarity. Here you go:
https://jsfiddle.net/hmLpdnqa/

Answer 2

You just included wrong bootstrap file. Try this and see your issue resolved or not.
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<div class="container">
<!-- ROW 1 -->
<div class="row">
<div class="col" align="center">
<h2>TITLE</h2> </div>
<div class="col" align="center">
<h2>TITLE</h2></div>
</div> <!-- ROW 1 -->
<!-- ROW 2 -->
<div class="row">
<div class="col-sm" align="center">
<input type="text" class="form-control" id="text" placeholder="text" required>
</div>
<div class="col-sm" align="center">
<input type="text" class="form-control" id="text" placeholder="text">
</div>
</div> <!-- ROW 2 -->
<br>
<div class="container" >
<div class="row">
<div class="col-sm">
<h2>TITLE</h2>
</div>
</div>
<div class="row">
<div class="col-sm">
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">text</span>
</div>
<input type="text" class="form-control" id='text' readonly>
</div>
</div>
</div>
</div>