Help plugin

tinymce.init({
  selector: 'textarea',  // change this value according to your HTML
  plugins: 'help',
  toolbar: 'help'
});

tinymce.init({
  selector: 'textarea',
  plugins: 'help link table paste code emoticons',
  toolbar: 'help addTab',
  help_tabs: [
    'shortcuts', // the default shortcuts tab
    'keyboardnav', // the default keyboard navigation tab
    'plugins', // the default plugins tab
    {
      name: 'custom1', // new tab called custom1
      title: 'Custom Tab 1',
      items: [
        {
          type: 'htmlpanel',
          html: '<p>This is a custom tab</p>',
        }
      ]
    },
    {
      name: 'versions', // override the default versions tab
      title: 'Custom Versions',
      items: [
        {
          type: 'htmlpanel',
          html: 'This is a custom versions panel.'
        }
      ]
    },
    'custom2', // new tab custom2 as defined on init in setup() below
    'custom3' // new tab custom3 as defined on button click in setup() below
  ],
  setup: function(editor) {
    // on editor init, add a tab called custom2
    editor.on('init', function() {
      editor.plugins.help.addTab({
        name: 'custom2',
        title: 'Custom Tab 2',
        items: [
          {
            type: 'htmlpanel',
            html: '<p>This is another custom tab</p>',
          }
        ]}
      );
    });

    // add a toolbar button that when clicked adds a tab called custom3
    editor.ui.registry.addButton('addTab', {
      text: 'Add tab',
      onAction: function() {
        editor.plugins.help.addTab({
          name: 'custom3',
          title: 'Custom Tab 3',
          items: [
            {
              type: 'htmlpanel',
              html: '<p>This is yet another custom tab</p>',
            }
          ]
        });
      }
    });
  }
});

tinymce.activeEditor.plugins.help.addTab({
  name: 'custom',
  title: 'My Custom Tab',
  items: [
    {
      type: 'htmlpanel',
      html: '<p>This is a custom tab</p>',
    }
  ]
});

tinymce.activeEditor.execCommand('mceHelp');