<html>
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Rich Text Editor</title>
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.2.3/dist/css/bootstrap.min.css">
  <link rel="stylesheet" href="https://cdn.quilljs.com/1.3.7/quill.snow.css">
</head>
<body>
  <div class="container mt-5">
    <h1>Rich Text Editor</h1>
    <div id="editor"></div>
  </div>

  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.2.3/dist/js/bootstrap.min.js"></script>
  <script src="https://cdn.quilljs.com/1.3.7/quill.js"></script>
  <script>
    var toolbarOptions = [
      ['bold', 'italic', 'underline', 'strike'],        // toggled buttons
      ['blockquote', 'code-block'],

      [{ 'header': 1 }, { 'header': 2 }],               // custom button values
      [{ 'list': 'ordered'}, { 'list': 'bullet' }],
      [{ 'script': 'sub'}, { 'script': 'super' }],      // superscript/subscript
      [{ 'indent': '-1'}, { 'indent': '+1' }],          // outdent/indent
      [{ 'direction': 'rtl' }],                         // text direction

      [{ 'size': ['small', false, 'large', 'huge'] }],  // custom dropdown
      [{ 'header': [1, 2, 3, 4, 5, 6, false] }],

      [{ 'color': [] }, { 'background': [] }],          // dropdown with defaults from theme
      [{ 'font': [] }],
      [{ 'align': [] }],

      ['clean']                                         // remove formatting button
    ];

    var quill = new Quill('#editor', {
      modules: {
        toolbar: toolbarOptions
      },
      theme: 'snow'
    });
  </script>
</body>
</html>

An HTML file with a Bootstrap-based rich text editor that uses Quill.js