There are two options available for you to use JQuery framework. First option is to download the JQuery file directly from the following website.
Download the JQuery framework library from https://jquery.com.
Second alternative is to use CDN. CDN stands for Content Delivery Network. This option is better because it will download from the closest server to your visitor's location, therefore it will have a better performance impact for your user experience.
You can either include this google CDN link on your website. It is recommended you put this link into the footer of your page. You can put it on the header of your page if you want. The difference is if you place it on your footer, the user does not need to wait for their browser to download the library. On the other hand, you have to make sure your code requires JQuery to be loaded after the browser has completely loaded the content.
Or you can use the CDN directly from JQuery.
https://code.jquery.com/jquery-2.1.4.min.js