Add sizes for Bootstrap Buttons

To add size for buttons in Bootstrap, try the following classes:

Class	Description
.btn-lg	This makes the button size large.
.btn-sm	This makes the button size small.
.btn-xs	This makes the button size extra small.
.btn-block	This creates block level buttons—those that span the full width of a parent.

Example

You can try to run the following code to create a small button −

<!DOCTYPE html>
<html>
   <head>
      <title>Bootstrap Example</title>  
      <meta name = "viewport" content = "width = device-width, initial-scale = 1">
      <link rel = "stylesheet" href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css">
      <script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
   </head>
   <body>
      <button type = "button" class = "btn btn-default btn-sm">
         Small button
      </button>
   </body>
</html>