In your JS File add this option to your datatable:
buttons: [ 'excel', 'pdf', 'copy' ]
It will look like:
$('#yourTableID').DataTable({
buttons: [ 'excel', 'pdf', 'copy' ]
});
Add the necessary css files for the datatable with the buttons:
<link rel="stylesheet" type="text/css" href="//cdn.datatables.net/1.10.15/css/dataTables.bootstrap4.min.css"/>
<link rel="stylesheet" type="text/css" href="//cdn.datatables.net/buttons/1.3.1/css/buttons.bootstrap4.min.css"/>
Add the necessary javascript files for the datatable with the buttons:
<script type="text/javascript" src="//cdn.datatables.net/1.10.15/js/jquery.dataTables.min.js"></script>
<script type="text/javascript" src="//cdn.datatables.net/1.10.15/js/dataTables.bootstrap4.min.js"></script>
<script type="text/javascript" src="//cdn.datatables.net/buttons/1.3.1/js/dataTables.buttons.min.js"></script>
<script type="text/javascript" src="//cdn.datatables.net/buttons/1.3.1/js/buttons.bootstrap4.min.js"></script>
<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/jszip/3.1.3/jszip.min.js"></script>
<script type="text/javascript" src="//cdn.rawgit.com/bpampuch/pdfmake/0.1.27/build/pdfmake.min.js"></script>
<script type="text/javascript" src="//cdn.rawgit.com/bpampuch/pdfmake/0.1.27/build/vfs_fonts.js"></script>
<script type="text/javascript" src="//cdn.datatables.net/buttons/1.3.1/js/buttons.html5.min.js"></script>
It will look like this picture:
If you doesn't see the buttons, add this option:
dom: 'Blfrtip',
to the datatable options list. So it looks like:
$('#yourTableID').DataTable({
dom: 'Blfrtip',
buttons: [ 'excel', 'pdf', 'copy' ]
});
You will find more informations to define the table control elements to appear on the page and in what order on this page.
Note: The prerequisite is, that the jQuery and bootstrap4 files are installed in your project.