Jquery code addition

I’m working on a animated presentation for a management team page. I’ve read that jquery has been part of WordPress since 3.8.1, but that it is not available in all themes. So 2 questions:

1) Is jquery already added to the Customizr theme, or do I need to add it to the functions.php?

2) If jquery is available for a page, how do I add a Javascript snippet? how do I add a file of Javascript?