One of the ways to edit data is by using the Edit Dialog functionality. You can launch Edit Dialog by selecting a row and then clicking on the "Edit" button in the grid toolbar (bottom left in this example). For this, you need to have navigator enabled.
By default, columns are not editable. To make them editable, set the editable property of the respective column to true.
You can customize almost any feature of the edit dialog via the navigator options for edit dialog (for example Caption, SubmitButtonText, etc)
Please, take a look at the code in the HTML tab for additional details.