How can insert JQuery in WordPress? [closed]

WordPress gets delivered with jQuery. All you have to do is tell your theme to wp_enqueue_script() jQuery:

wp_enqueue_script( 'jquery' );

This code belongs into your functions.php. Of course, you can also change which version of jQuery should be loaded, and from which ressource, check this thread for further details.

Afterwards you can put your jQuery-magic into any javascript that is loaded within your theme.