title: Making a custom input text type
body: <p>I want to make this</p>
  
  <p><a href="https://i.stack.imgur.com/cjDyU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cjDyU.png" alt="enter image description here"></a></p>
  
  <p>but I don't know how to make the squares and how to set that in one square only one letter can be entered. So far I wrote this, but I really don't  know how to continue.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.input {
    width: 200px;
    border: 1px solid black;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;label&gt;&lt;b&gt;CNP&lt;/b&gt;&lt;/label&gt;
  &lt;input class="input" type="text" name="CNP"&gt;</code></pre>
  </div>
  </div>
  </p>