To add a checkbox next to a node in TreeView, specify the checkboxes attribute as true when initializing the TreeView widget:

$('#treeView').kendoTreeView({

  checkboxes: true

});

If you want the child nodes to be selected when the parent node is selected, then specify checkChildren as true:

$('#treeView').kendoTreeView({

    checkboxes: {
       checkChildren: true
    }

});

Now, when you select the parent node, all child nodes within the parent node would be selected. It is also possible to specify nodes as checked when they are rendered. In the DataSource configuration, specify checked as true:

$('#treeView').kendoTreeView({

  checkboxes: {
    checkChildren: true
  },

  dataSource: [{
    text: "Directory1",
    
    items: [ 
      {text: "File1.txt"}, 
      {text: "File2.txt"}...