W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<body>

<div class="w3-container">
<h2>Navigation Bar Sizes</h2>
<p>Add the w3-small, w3-large, w3-xlarge or w3-xxlarge to change the size of the navigation (will change the font-size of each link).</p>

<p>Default:</p>
<div class="w3-bar w3-border w3-green">
  <a href="#" class="w3-bar-item w3-button">Home</a>
  <a href="#" class="w3-bar-item w3-button">Link 1</a>
  <a href="#" class="w3-bar-item w3-button">Link 2</a>
  <a href="#" class="w3-bar-item w3-button">Link 3</a>
</div>

<p>w3-large:</p>
<div class="w3-bar w3-border w3-green w3-large">
  <a href="#" class="w3-bar-item w3-button">Home</a>
  <a href="#" class="w3-bar-item w3-button">Link 1</a>
  <a href="#" class="w3-bar-item w3-button">Link 2</a>
  <a href="#" class="w3-bar-item w3-button">Link 3</a>
</div>

<p>w3-xlarge:</p>
<div class="w3-bar w3-border w3-green w3-xlarge">
  <a href="#" class="w3-bar-item w3-button">Home</a>
  <a href="#" class="w3-bar-item w3-button">Link 1</a>
  <a href="#" class="w3-bar-item w3-button">Link 2</a>
  <a href="#" class="w3-bar-item w3-button">Link 3</a>
</div>

<p>w3-xxlarge:</p>
<div class="w3-bar w3-border w3-green w3-xxlarge">
  <a href="#" class="w3-bar-item w3-button">Home</a>
  <a href="#" class="w3-bar-item w3-button">Link 1</a>
  <a href="#" class="w3-bar-item w3-button">Link 2</a>
  <a href="#" class="w3-bar-item w3-button">Link 3</a>
</div>

<p>If you want more space between each link, instead of increasing the font-size, you could add a w3-padding-classes to each link:</p>
<div class="w3-bar w3-border w3-green">
  <a href="#" class="w3-bar-item w3-button w3-padding-16">Home</a>
  <a href="#" class="w3-bar-item w3-button w3-padding-16">Link 1</a>
  <a href="#" class="w3-bar-item w3-button w3-padding-16">Link 2</a>
  <a href="#" class="w3-bar-item w3-button w3-padding-16">Link 3</a>
</div>

</div>
</body>
</html>